essay on tsunami introduction

Essay on Tsunami for Students and Children

500+ words essay on tsunami.

Tsunami is a phenomenon where a series of strong waves that are responsible for the surge in water sometimes reach the heights in many meters. This is a natural disaster that is caused due to the volcano eruption in the ocean beds. Also, a phenomenon like landslides and earthquakes contributes to reasons for a tsunami. Like other natural disasters, the impact of the tsunami is also huge. It has been seen throughout history how disastrous the tsunami is. The essay on tsunami talks about various factors that contribute to the tsunami and the damage it causes to mankind. 

Essay on Tsunami

The disaster that is caused due to waves generated in the ocean because of the earthquake and whose main point is under the water is known as ‘Tsunami’. Also, the term tsunami is associated with tidal waves. Thus, a tsunami is also called as the series of ocean waves that have a very long wavelength. Because of the tsunami, there are strong waves of water is formed and this moves landwards. So, this causes inland movement of water which is very high and lasts for a long time. Thus, the impact of these waves is also very high. 

Greeks were the first people on Earth to claim the effects of the tsunami. They claim that tsunami is just like land earthquakes. Also, the only difference between tsunami and earthquake is that tsunami is caused in oceans. Thus, the scale and ferocity of the tsunami are almost impossible to control. 

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The History of Tsunami

The highest ever recorded tsunami was on 9th July 1958 in the record books. It took place in a bay which was located in the ligula bay along the coasts of Alaska. After the quake, a massive mass of rock fell into the bay waters from the cliff nearby. Thus, this created an impact and produced a wave that reached a height of 524 meters. Also, this is regarded as one of the highest recorded tsunami waves ever. 

The destructive waves responsible for the occurrence of tsunami is also produced in waters of bays or lakes. As this water approached the coast, it grows larger. However, the size of this wave is very low in deep-sea areas. Tsunami waves that are generated in the lakes or bays do not travel for a long distance. Thus, they are not as destructive as the ones produced in the ocean waters. There are various directions in which tsunami can travel from the main point. 

One similar devastating tsunami was experienced in India in 2004. However, the origin of this tsunami was located near Indonesia. Because of the tsunami, it was expected that a total of 2 lakh people lost their lives. The waves traveled extensively thousands of kilometers in countries like Thailand, India, Indonesia, Sri Lanka, Bangladesh, and the Maldives. 

Tsunamis occur mainly in the Pacific Ocean. There are very chances that they take place in the area where there are larger bodies. Coastlines and open bays next to very deep waters may help tsunami further into a step-like wave. 

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Essay on tsunami: top 8 essays | natural disasters | geography.

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Here is a compilation of essays on ‘Tsunami’ for class 6, 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Tsunami’ especially written for school and college students.

Essay on Tsunami

Essay Contents:

• Essay on the Research on Tsunami Disaster Prevention 

Essay # 1. Meaning of Tsunami :

When a large earthquake happens beneath an ocean floor, it can change the level of the floor suddenly, raising and lowering it substantially. This produces a large disturbance in the sea. The size and energy of disturbance depends on the magnitude of the earth quake.

Most severe earthquakes occur near the subduction zone of the tectonic plates. A wave starts spreading out. The height of the wave might be only a few meters, but this wave is very different from the normal oceanic waves produced by the action of the wind on the surface.

This wave invokes up and down movement of the whole column of the ocean above the affected zone that might be hundreds of kilometres in length.

The speed of the wave in the deep ocean is nearly the same as the cruising speed of a jet liner, namely 7-8 hundred kilometres per hour. In the middle of the ocean surface, this wave might be seen as a gentle swell and fall of the ocean surface and does not represent a major hazard to boats and ships. But it becomes dangerously high and devastating when it approaches the coast. This is called the much feared tsunami.

Tsunami (pronounced tsoo – nah – mee) is a Japanese word, which means ‘harbour wave’. Tsu means harbour and nami stands for wave. Tsunamis are large waves that are generated when the sea floor is deformed by seismic activity, vertically displacing the overlying water in the ocean.

An earthquake occurred with its epicentre 257km south-southwest of Sumatra in December 2004. The magnitude of the earthquake was 8.9 on the Richter scale. That is why, it was most powerful in the world in the past 40 years.

Most of the destruction was caused by seismic waves or tsunami that hit India, Sri Lanka, Malaysia and Thailand within two hours of the first impact of earthquake. This earthquake was the world’s fifth most powerful, since 1900 and the strongest since a 9.2 temblor slammed Alaska in 1964, U.S. earthquake.

It has been observed that the Sumatra quake occurred at a place where several massive geological plates push against each other with a strong force. The survey indicates that 1000 km section along the boundary of the plates shifted motion that triggered the sudden displacement, causing the huge tsunamis.

It may be several meters high when it hits the sea shore. Tsunami may not be one giant wave but a series of waves that come to the coast in a short interval.

An earthquake occurred on 8 th May, 2008 at Siachuan in China, which caused widespread destruction. Another earthquake occurred on 11 th April, 2012 with powerful magnitude about 500 km south-west of Banda Aceh, on the northern tip of Indonesia’s Sumatra island.

The magnitude of the earthquake was 8.6 on the Richter scale. The termors of varying intensity were felt in Tamilnadu, Andhra Pradesh, Karnataka, Kerala and West Bengal. However, this time earthquake has not caused widespread destruction and loss of lives, because the strength of tsunami was very low.

Essay # 2. Causes of Tsunami:

The principal generation mechanism (or cause) of a tsunami is the displacement of a substantial volume of water or perturbation of the sea. This displacement of water is usually attributed to earthquakes, landslides, volcanic eruptions and glacier calvings or more rarely by meteorites and nuclear test. The waves formed in this way are then sustained by gravity. Tides do not play any part in the generation of tsunamis.

Seismicity:

Tsunami can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the Earth’s crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position.

More specifically, a tsunami can be generated when thrust faults associated with convergent or destructive plate boundaries move abruptly, resulting in water displacement, owing to the vertical component of movement involved. Movement on normal faults will also cause displacement of the seabed, but the size of the largest of such events is normally too small to give rise to a significant tsunami.

Tsunamis have a small amplitude (wave height) offshore, and a very long wavelength (often hundreds of kilometers long, whereas normal ocean waves have a wavelength of only 30 or 40 meters), [30] which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimeters (12) above the normal sea surface. They grow in height when they reach shallower water, in a wave shoaling process described below. A tsunami can occur in any tidal state and even at low tide can still inundate coastal areas.

On April 1, 1946, a magnitude-7.8 (Richter scale) earthquake occurred near the Aleutian Islands, Alaska. It generated a tsunami which inundated Hilo on the island of Hawaii with a 14-metre high (46 ft.) surge. The area where the earthquake occurred is where the Pacific Ocean floor is subducting (or being pushed downwards) under Alaska.

Examples of tsunami originating at locations away from convergent boundaries include Storegga about 8,000 years ago, Grand Banks 1929, Papa New Guinea 1998. The Grand Banks and Papua New Guinea tsunamis came from earthquakes which destabilised sediments, causing them to flow into the ocean and generate a tsunami. They dissipated before traveling transoceanic distances. The cause of the Storegga sediment failure is unknown. Possibilities include an overloading of the sediments, an earthquake or a release of gas hydrates (methane etc.)

Landslides :

In the 1950s, it was discovered that larger tsunamis than had previously been believed possible could be caused by giant submarine landslides. These rapidly displace large water volumes, as energy transfers to the water at a rate faster than the water can absorb. Their existence was confirmed in 1958, when a giant landslide in Lituya Bay, Alaska, caused the highest wave ever recorded, which had a height of 524 meters (over 1700 feet).

The wave did not travel far, as it struck land almost immediately. Two people fishing in the bay were killed, but another boat amazingly managed to ride the wave. Another landslide-tsunami event occurred in 1963 when a massive landslide from Monte Toe went into the Vajont Dam in Italy.

The resulting wave overtopped the 262 m (860 ft.) high dam by 250 meters (820 ft.) and destroyed several towns. Around 2,000 people died. Scientists named these waves mega tsunami. Scientists discovered that extremely large landslides from volcanic island collapses may be able to generate mega tsunamis that can cross oceans.

In general, landslides generate displacements mainly in the shallower parts of the coastline, and there is conjecture about the nature of truly large landslides that end in water. This is proven to lead to huge effect in closed bays and lakes, but an open oceanic landslide large enough to cause a tsunami across an ocean has not yet happened since before seismology has been a major area of scientific study, and only very rarely in human history.

Susceptible areas focus for now on the islands of Hawaii and La Palma in the Canary Islands, where large masses of relatively unconsolidated volcanic shield on slopes occur. Considerable doubt exists about how loosely linked these slopes actually are.

Meteotsunamis :

Some meteorological condition, especially deep depressions such as tropical cyclones, can generate a type of storm surge called ameteotsunami which raises water heights above normal levels, often suddenly at the shoreline. In the case of deep tropical cyclones, this is due to very low atmospheric pressure and inward swirling winds causing an uplifted dome of water to form under and travel in tandem with the storm. When these water domes reach shore, they rear up in shallows and surge laterally like earthquake-generated tsunamis, typically arriving shortly after landfall of the storm’s eye.

Man-made or Triggered Tsunamis :

There have been studies and at least one attempt to create tsunami waves as a tectonic weapon or whether human behavior may trigger tsunamis, e.g., in the (debunked). In World War II, the New Zealand Military Forces initiated Project Seal, which attempted to create small tsunamis with explosives in the area of today’s Shakespeare Regional Park; the attempt failed.

There has been considerable speculation on the possibility of using nuclear weapons to cause tsunamis near to an enemy coastline. Even during World War II consideration of the idea using conventional explosives was explored. Nuclear testing in the Pacific Proving Ground by the United States seemed to generate poor results.

Operation Cross roads fired two 20 kilotonnes of TNT (84 TJ) bombs, one in the air and one underwater, above and below the shallow (50 m (160 ft.)) waters of the Bikini Atoll lagoon. Fired about 6 km (3.7 mi) from the nearest island, the waves there were no higher than 3-4 m (9.8-13.1 ft.) upon reaching the shoreline.

Other underwater tests, mainly Hardtack I/Wahoo (deep water) and Hardtack 1/ Umbrella (shallow water) confirmed the results. Analysis of the effects of shallow and deep underwater explosions indicate that the energy of the explosions doesn’t easily generate the kind of deep, all-ocean waveforms which are tsunamis; most of the energy creates steam, causes vertical fountains above the water, and creates compressional waveforms. Tsunamis are hallmarked by permanent large vertical displacements of very large volumes of water which don’t occur in explosions.

Essay # 3. Damages Caused by Tsunami:

Tsunamis cause damage by two mechanisms:

The smashing force of a wall of water travelling at high speed, and the destructive power of a large volume of water draining off the land and carrying a large amount of debris with it, even with waves that do not appear to be large. While everyday wind waves have a wavelength (from crest to crest) of about 100 meters (330 ft.) and a height of roughly 2 meters (6.6 ft.), a tsunami in the deep ocean has a much larger wavelength of up to 200 kilometers (120 mi).

Such a wave travels at well over 800 kilometers per hour (500 mph), but owing to the enormous wavelength the wave oscillation at any given point takes 20 or 30 minutes to complete a cycle and has an amplitude of only about 1 meter (3.3 ft.). This makes tsunamis difficult to detect over deep water, where ships are unable to feel their passage.

The reason for the Japanese name “harbour wave” is that sometimes a village’s fishermen would sail out, and encounter no unusual waves while out at sea fishing, and come back to land to find their village devastated by a huge wave. As the tsunami approaches the coast and the waters become shallow, wave shoaling compresses the wave and its speed decreases below 80 kilometers per hour (50 mph).

Its wavelength diminishes to less than 20 kilometers (12 mi) and its amplitude grows enormously. Since the wave still has the same very long period, the tsunami may take minutes to reach full height. Except for the very largest tsunamis, the approaching wave does not break, but rather appears like a fast-moving tidal bore. Open bays and coastlines adjacent to very deep water may shape the tsunami further into a step-like wave with a steep-breaking front.

When the tsunami’s wave peak reaches the shore, the resulting temporary rise in sea level is termed run up. Run up is measured in meters above a reference sea level. A large tsunami may feature multiple waves arriving over a period of hours, with significant time between the wave crests. The first wave to reach the shore may not have the highest run up. About 80% of tsunamis occur in the Pacific Ocean, but they are possible wherever there are large bodies of water, including lakes. They are caused by earthquakes, landslides, volcanic explosions, glacier calvings, and bolides.

Essay # 4. Drawback of Tsunami :

An illustration of rhythmic drawback of surface water associated with a wave that follows a very large drawback may herald the arrival of very large wave.

All waves have a positive and negative peak, i.e., a ridge and a trough. In the case of a propagating wave like a tsunami, either may be the first to arrive. If the first part to arrive at shore is the ridge, a massive breaking wave or sudden flooding will be the first effect noticed on land.

However, if the first part to arrive is a trough, a drawback will occur as the shoreline recedes dramatically, exposing normally submerged areas. Drawback can exceed hundreds of meters, and people unaware of the danger sometimes remain near the shore to satisfy their curiosity or to collect fish from the exposed seabed.

A typical wave period for a damaging tsunami is about 12 minutes. This means that if the drawback phase is the first part of the wave to arrive, the sea will recede, with areas well below sea level exposed after 3 minutes. During the next 6 minutes the tsunami wave trough builds into a ridge, and during this time the sea is filled in and destruction occurs on land. During the next 6 minutes, the tsunami wave changes from a ridge to a trough, causing flood waters to drain and drawback to occur again. This may sweep victims and debris some distance from land. The process repeats as the next wave arrives.

Essay # 5. Scales of Inten sity And Magnitude of Tsunami:

As with earthquakes, several attempts have been made to set up scales of tsunami intensity or magnitude to allow comparison between different events.

Intensity Scales:

The first scales used routinely to measure the intensity of tsunami were the Sieberg- Ambraseys scale, used in the Mediterranean Sea and the Imamura-Iida intensity scale, used in the Pacific Ocean.

The latter scale was modified by Soloviev, who calculated the Tsunami intensity I according to the formula:

where H av is the average wave height along the nearest coast. This scale, known as the Soloviev-Imamura tsunami intensity scale, is used in the global tsunami catalogues compiled by the NGDC/NOAA and the Novosibirsk Tsunami Laboratory as the main parameter for the size of the tsunami.

In 2013, following the intensively studied tsunamis in 2004 and 2011, a new 12 point scale was proposed, the Integrated Tsunami Intensity Scale (ITIS-2012), intended to match as closely as possible to the modified ESI2007 and EMS earthquake intensity scales.

Magnitude Scales :

The first scale that genuinely calculated a magnitude for a tsunami, rather than an intensity at a particular location was the ML scale proposed by Murty and Loomis based on the potential energy. Difficulties in calculating the potential energy of the tsunami mean that this scale is rarely used. Abe introduced the tsunami magnitude scale M t , calculated from,

M t = a log h + b log R = D

where h is the maximum tsunami-wave amplitude (in m) measured by a tide gauge at a distance R from the epicenter, a, b and D are constants used to make the Mt scale match as closely as possible with the moment magnitude scale.

Essay # 6. Tsunami Warning Sign :

Drawbacks can serve as a brief warning. People who observe drawback (many survivors report an accompanying sucking sound), can survive only if they immediately run for high ground or seek the upper floors of nearby buildings. In 2004, ten-year-old Tilly Smith of Surrey, England, was on Maikhao beach in Phuket, Thailand with her parents and sister, and having learned about tsunamis recently in school, told her family that a tsunami might be imminent. Her parents warned others minutes before the wave arrived, saving dozens of lives. She credited her geography teacher, Andrew Kearney.

In the 2004 Indian Ocean tsunami drawback was not reported on the African coast or any other east-facing coasts that it reached. This was because the wave moved downwards on the eastern side of the fault line and upwards on the western side. The western pulse hit coastal Africa and other western areas.

A tsunami cannot be precisely predicted, even if the magnitude and location of an earthquake is known. Geologists, oceano graphers, and seismologists analyse each earthquake and based on many factors may or may not issue a tsunami warning. However, there are some warning signs of an impending tsunami, and automated systems can provide warnings immediately after an earthquake in time to save lives. One of the most successful systems uses bottom pressure sensors, attached to buoys, which constantly monitor the pressure of the overlying water column.

Regions with a high tsunami risk typically use tsunami warning systems to warn the population before the wave reaches land. On the west coast of the United States, which is prone to Pacific Ocean tsunami, warning signs indicate evacuation routes. In Japan, the community is well-educated about earthquakes and tsunamis, and along the Japanese shorelines the tsunami warning signs are reminders of the natural hazards together with a network of warning sirens, typically at the top of the cliff of surroundings hills.

The Pacific Tsunami Warning System is based in Honolulu, Hawaii. It monitors Pacific Ocean seismic activity. A sufficiently large earthquake magnitude and other information triggers a tsunami warning. While the subduction zones around the Pacific are seismically active, not all earthquakes generate tsunami. Computers assist in analysing the tsunami risk of every earthquake that occurs in the Pacific Ocean and the adjoining land masses.

Essay # 7. Questions for Tsunami Preparedness:

Millions of people around the world live in areas at risk for tsunamis, such as Hawaii, Alaska, the US and Canadian coasts, Indonesia, Sri Lanka, Thailand, and India and millions more visit these places every day.

In the event of a tsunami, following are answers to the most commonly asked questions:

1. What is a Tsunami?

A tsunami is a series of ocean waves generated by sudden movements in the sea floor, landslides, or volcanic activity. In the deep ocean, the tsunami wave may only be a few inches high. The tsunami wave may come gently ashore or may increase in height as it gets closer to shore to become a fast moving wall of turbulent water several meters high.

2. Are Tsunamis Common?

Tsunamis are quite rare compared to other hazardous natural events, but they can be just as deadly and destructive. As a result of their rarity, tsunami hazard planning along the US and Canadian west coasts, Alaska and within the Pacific Region is inconsistent. Even in locations with a history of deadly tsunamis, an adequate level of awareness and preparedness is difficult to achieve.

3. Can a Tsunami be prevented?

Although a tsunami cannot be prevented, the effect of a tsunami can be reduced through community preparedness, timely warnings, and effective response. NOAA is leading the world in providing tsunami observations and research. Through innovative programs, NOAA is helping coastal communities prepare for possible tsunamis to save lives and protect property.

High Resolution :

NOAA’s Tsunami Warning System (TWS) monitors the Pacific Basin for potential tsunami activity. As part of the TWS, NOAA operates two Tsunami Warning Centers in Alaska and Hawaii. The Alaska Tsunami Warning Center serves as the regional Tsunami Warning Center for Alaska, British Columbia, Washington, Oregon, and California.

The Pacific Tsunami Warning Center serves as the regional Tsunami Warning Center for Hawaii and as a national/international warning center for tsunamis that pose a Pacific-wide threat. When tsunami activity is detected, NOAA issues tsunami watch, warning, and information bulletins to appropriate emergency officials and the general public by a variety of communication methods.

The warning includes predicted tsunami arrival times at selected coastal communities within the geographic area defined by the maximum distance the tsunami could travel in a few hours. If a significant tsunami is detected, the tsunami warning is extended to the entire Pacific Basin.

Because of the December 2004 tsunami in South Asia, NOAA is expanding the US Tsunami Warning Program. This expansion will increase the current Pacific Ocean network of 6 DART Buoys to 39 in the Pacific and Atlantic Oceans and the Caribbean Sea, establish an Atlantic Tsunami Warning Center, deploy second generation buoys, and expand the Tsunami Mitigation Program including outreach and education.

Can the Damage be Minimized?

Yes. For example, the State of Hawaii is addressing tsunami risk through the Hazard Education and Awareness Tool (HEAT), a Web site template that uses Google Maps technology, spatial hazard data, and preparedness information to help increase awareness of coastal hazards.

NOAA’s Pacific Services Center used HEAT to develop a tsunami information service that provides residents and visitors convenient, online access to interactive evacuation zone maps, along with the education and awareness information needed to be prepared in the event of a tsunami. HEAT project partners in Hawaii include state and local planning and civil defense officials, the Red Cross and other disaster relief agencies.

What Can You Do?

Develop a Family Disaster Plan. Learn about tsunami risk in your community. Find out if your home, school, workplace or other frequently visited locations are in tsunami hazard areas. Know the height of your street above sea level and its distance from the coast or other high-risk waters. Evacuation orders may be based on these numbers. Find out if your community is Tsunami Ready.

If you are visiting an area at risk from tsunamis, check with the hotel, motel, or campground operators for tsunami evacuation information and how you would be warned.

It is important to know designated escape routes before a warning is issued:

I. Plan an Evacuation Route:

Plan an evacuation route from your home, school, workplace, or any other place you’ll be where tsunamis present a risk. If possible, pick an area 100 feet above sea level or go up to two miles inland, away from the coastline. If you can’t get this high or far, go as high as you can. Every foot inland or upwards may make a difference.

II. Practice your Evacuation Route:

Familiarity may save your life. Be able to follow your escape route at night and during inclement weather. Practicing your plan makes the appropriate response more instinctive, requiring less thinking during an actual emergency situation.

III. Get a NOAA Weather Radio:

Use a NOAA Weather Radio with a tone-alert feature to keep you informed of local watches and warnings. The tone alert feature will warn you of potential danger even if you are not currently listening to local radio or television stations.

IV. Talk to Your Insurance Agent:

Homeowners’ policies do not cover flooding from a tsunami. Ask about the National Flood Insurance Program.

V. Discuss Tsunami Preparedness with Your Family:

Everyone should know what to do in case all family members are not together. Discussing the dangers of tsunamis and your evacuation plans ahead of time will help reduce fear and anxiety, and let everyone know how to respond. Review flood safety and preparedness measures with your family.

VI. Prepare the essentials:

Prepare a supply kit equipped to sustain you and your family for about a week and make sure it is readily accessible in case you need to take quick action.

VII. Have a Pet Plan:

Sheltering your pet or evacuating it with you can have an effect on your overall plan. You may need to take special steps to make sure your pet is safe before, during, and after the disaster.

VIII. Heed Warnings:

When local and state officials issue warnings and evacuation notices, adhere to their directions and implement your disaster plan immediately.

IX. Make your community Tsunami Ready:

The Tsunami Ready Program, developed by NOAA’s National Weather Service, is designed to help cities, towns, counties, universities and other large sites in coastal areas reduce the potential for disastrous tsunami- related consequences.

X. Tsunami Ready helps community leaders and emergency managers strengthen their local operations. Tsunami Ready communities are better prepared to save lives through better planning, education and awareness. Communities have fewer fatalities and property damage if they plan before a tsunami arrives. No community is tsunami proof, but Tsunami Ready can help minimize loss to your community.

Essay # 8. Research on Tsunami Disaster Prevention :

Background :

Looking at the history globally Japan has suffered from repeated tsunami-caused damage, and massive tsunamis are anticipated as a result of mega-thrust earthquakes such as the Tokai, Tonankai and Nankai earthquakes. PARI and other institutions have conducted research on tsunami disaster prevention and mitigation. However, the 2011 Great East Japan Earthquake and Tsunami resulted in unprecedented damage.

When considering the possibility of giant tsunamis in the future such as those in 2011, further research and development are needed to save people’s lives, reduce economic loss, and make early restoration and reconstruction possible. This research theme therefore involves engineering oriented research and development in regard to tsunami propagation and inundation, stability of structures against tsunamis, combined earthquake/tsunami disasters, etc.

Areas for future research:

(i) Research on combined Earthquake/Tsunami Disasters:

Regarding a combined earthquake/tsunami disaster caused by a large mega-thrust earthquake, we investigate disaster mechanisms on the basis of laboratory experiments and develop numerical models for disaster prediction. The experimental studies involve the development of facilities combining a geotechnical centrifuge and a tsunami flume.

(ii) Research on developing structural measures for tsunami disaster mitigation and early restoration:

We develop countermeasures to control damage of structures caused by tsunamis exceeding the design parameters, performance verification methods to predict structure displacement, and hardware technologies to reduce tsunami energy,

(iii) Research on developing software for tsunami disaster mitigation and early restoration:

In addition to a real-time tsunami hazard mapping technology, we are developing an evacuation simulator to ensure early evacuation. We also explore ship motions induced by tsunami attacks, and consider safer procedures for ship evacuation. Moreover, we review scenario creation techniques including early recovery of ports, and promote practical use of such scenarios.

Activities in this Area:

1. Hydraulic model experiments were carried out to study the mechanisms of destruction of breakwaters in order to establish resilient structures to tsunamis higher than the design tsunami, given the damage caused by tsunamis in the Great East Japan Earthquake. At the same time, model experiments were carried out to examine the mechanisms in the destruction of embankments, parapets, coastal dikes, and tsunami evacuation buildings. Furthermore, we carried out model experiments to study the behavior of and countermeasures against containers and other objects washed away by tsunamis.

2. The mathematical simulation model of Storm Surge and Tsunami Simulator in Oceans and Coastal areas (STOC) developed by PARI were improved to enable computation of wave breaking of tsunamis and scouring and topographical changes to ports caused by tsunamis. The model was successfully validated in comparison with the tsunamis striking in Kuji Port and Hachinohe Port especially at the catastrophic event in 2011.

Furthermore, we elucidated the behavior of ships affected by the tsunami at Kashima Port through analysis of Automatic Identification System (AIS) data and identification of issues surrounding calculations of ship drift through numerical simulations.

3. In regard to mitigating damage from tsunamis, we implemented instant tsunami inundation forecasting technology (real time tsunami hazard mapping), using offshore tsunami measurement data acquired through GPS-equipped buoys, in a pilot site of Nagoya Port. We demonstrated that it is possible to forecast inundation area in Nagoya Port approximately two minutes after measurement of the peak of the first tsunami wave by the GPS-equipped buoys. These results were reported to the investigative commission on utilizing offshore wave detection systems set up by the Chubu Regional Bureau.

4. In regard to restoration and rehabilitation after being struck by tsunamis, simulations of the expected tsunami propagation, inundation, and drifting of ships and containers were carried out using STOC, in Shimizu Port. Simulations took the subsidence of breakwaters into account in predicting potential damage caused by tsunamis, based on Cabinet Office assumptions of what a Nankai Trough Earthquake would be like.

5. Development an evacuation simulator enabling analyses of the behaviour of agent models that simulate the evacuation of people through modeling of the intelligent behavior of people. This will enable clarification of the relationship between the inundation delaying effect of tsunami protection facilities and evacuation. Moreover, the “Tenth International Workshop on Coastal Disaster Prevention” was held in Santiago, Chile, on December 11, 2012, jointly organized with the cooperation of the Coastal Development Institute of Technology, Japan International Cooperation Agency (JICA), Japan Science and Technology Agency (JST), Pontifical Catholic University of Chile and the Ministry of Public Works of Chile. Information was shared on the current status of numerical tsunami computation technology, countermeasures against tsunamis, etc., and discussions were held on prevention of future tsunami disasters.

Furthermore, this workshop was held in conjunction with the “Second Japan-Chile Symposium on Tsunami Disaster Mitigation” which was an outreach activity of the SATREPS (Science and Technology Research Partnership for Sustainable Development) Chile project.

6. We have led the SATREPS Chile project since 2011, collaborating with Kansai University, the Japan Agency for Marine- Earth Science and Technology, Yamaguchi University and other universities, institutions and the Ministry of Land, Infrastructure, Transport and Tourism in Japan as well as Chilean universities, institutions and administrative bodies, that was funded by JST and JICA. Technical support in tsunami computation technology was also given to Chilean researchers and engineers as another activity of the project.

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Tsunami Essay | Essay on Tsunami for Students and Children in English

February 13, 2024 by sastry

Tsunami Essay: The term Tsunami comes from the Japanese language and means harbour wave. Tsunamis are seismic waves that are caused by earthquakes which travel through water. An earthquake that is too small to create a tsunami by itself may trigger an undersea landslide quite capable of generating a tsunami.

You can read more  Essay Writing  about articles, events, people, sports, technology many more.

Long and Short Essays on Tsunami for Kids and Students in English

Given below are two essays in English for students and children about the topic of ‘Tsunami’ in both long and short form. The first essay is a long essay on Tsunami of 400-500 words. This long essay about Tsunami is suitable for students of class 7, 8, 9 and 10, and also for competitive exam aspirants. The second essay is a short essay on Tsunami of 150-200 words. These are suitable for students and children in class 6 and below.

Long Essay on Tsunami 500 Words in English

Below we have given a long essay on Tsunami of 500 words is helpful for classes 7, 8, 9 and 10 and Competitive Exam Aspirants. This long essay on the topic is suitable for students of class 7 to class 10, and also for competitive exam aspirants.

Tsunami can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Such large vertical movements of the earth’s crust can occur at plate boundaries. Although often referred to as ‘tidal waves’, a tsunami does not look like the popular impression of ‘a normal wave only much bigger’. Instead, it looks rather like an endlessly onrushing tide which forces its way around and through any obstacle. Most of the damage is caused by the huge mass of water behind the initial wave front, as the height of the sea keeps rising fast and floods powerfully into the coastal areas. The sheer weight of water is enough to pulverise objects in its path, often reducing buildings to their foundations and scouring exposed ground to the bedrock. Large objects such as ships and boulders can be carried several miles inland before, a Tsunami subsides.

It is said that the Greek historian Thucydides proposed that Tsunamis had some relation to submarine earthquakes. However, the understanding of Tsunami’s nature and causes remained weak until the 20th century. Roman historian, Ammianus described the order of events giving rise to a Tsunami: an earthquake, sudden retreat of the sea followed by a gigantic wave. Japan has the longest recorded history of Tsunamis. The 2004 Indian Ocean earthquake cum Tsunami is marked as one of the most devastating in modern times, taking the death toll to around 2,30,000 people. The Sumatran region also experiences earthquakes off the coast regularly.

Recently, it has been discovered that larger Tsunamis than previously believed possible could be caused by landslides, explosive volcanic actions and Earth-scouring impact events. These phenomena rapidly displace large volumes of water, as energy from falling debris or expansion is transferred to the water into which the debris fall. Tsunamis caused by these mechanisms, unlike the ocean-wide tsunamis caused by some earthquakes, generally dissipate quickly and rarely affect coastlines distant from the source due to the small area of the sea affected.

Tsunamis move the entire depth of the ocean (often several kilometres deep) rather than just the surface, so they contain immense energy, propagate at high speeds and can travel great trans-oceanic distances with little overall energy loss. A Tsunami can cause damage thousands of kilometres from its origin, so there may be several hours between its creation and its impact on a coast, arriving long after the seismic wave generated by the originating event arrives.

In open water, Tsunamis have extremely long periods from minutes to hours, and long wavelengths of up to several hundred kilometres. This is very different from typical wind-generated swells on the ocean, which might have a period of about 10 seconds and a wavelength of 150 metres.

A few signs may be triggered by nature to warn a huge tsunami wave. An earthquake may be felt. Large quantities of gas may bubble to the water surface and make the sea look as if it is boiling. The water in the waves may be unusually hot. The water may sometimes smell of rotten eggs due to the presence of hydrogen sulphide or of petrol or oil. The water may sting the skin.

A thunderous boom may be heard followed by a roaring noise as of a jet plane, a helicopter, or a whistling sound. The sea may recede to a considerable distance.

A flash of red light might be seen near the horizon and as the wave approaches, the top of the wave may glow red. These signals have been recorded from time to time over the ages before every Tsunami tragedy. Oceanographers, scientists, geologists and environmentalists are working on making some kind of systems which can if not prevent atleast signal the impending Tsunami.

The Lisbon quake is the first documented case of such a phenomenon in Europe back in 1 755 which had generated an almost 12 metre high sea wave and had destroyed most part of the city killing around 60000 people. This phenomenon was also seen in Sri Lanka in the 2004 Indian Ocean earthquake. In 2011, the powerful 8.9 magnitude earthquake sent Japan into chaos as it triggered a giant tsunami in the Pacific Ocean, sweeping away boats, cars, homes and people, and led to the loss of more than 15000 lives in Japan.

In some particularly Tsunami-prone countries, measures have been taken to reduce the damage caused on the shores. Japan has implemented an extensive programme of building Tsunami walls of up to 4.5m (13.5 ft) high in front of populated coastal areas. Other localities have built floodgates and channels to redirect the water from incoming tsunamis. However, their effectiveness has been questioned, as Tsunamis are often higher than the barriers.

For instance, the Tsunami which hit the island of Hokkaido on 12 July, 1993 created waves as much as 30 m (100 ft) tall – as high as a 10-storey building. The port town of Aonae was completely surrounded by a Tsunami wall but the waves washed right over the wall and destroyed all the wood-framed structures in the area.

The wall may have succeeded in slowing down and moderating the height of the Tsunami but it did not prevent major destruction and loss of life.

Yet the effects of a Tsunami can be mitigated by natural factors such as tree cover on the shoreline. Some locations in the path of the 2004 Indian Ocean Tsunami escaped almost unscathed as a result of the tsunami’s energy being sapped by a belt of trees such as coconut, palms and mangroves. In one striking example, the village of Naluvedapathy in India’s Tamil Nadu region suffered minimal damages and few deaths as the wave broke up on a forest of 80244 trees planted along the stretches of seacoasts that are prone to Tsunami risks.

While it would take some years for the trees to grow to a useful size, such plantations could offer a much cheaper and longer-lasting means of Tsunami mitigation than the costly and environmentally destructive method of erecting artificial barriers.

Short Essay on Tsunami 200 Words in English

Below we have given a short essay on Tsunami is for Classes 1, 2, 3, 4, 5 and 6. This short essay on the topic is suitable for students of class 6 and below.

Regions with a high risk of Tsunamis may use Tsunami warning systems now available to detect Tsunamis and warn the general populace before the waves reach the coasts. In some communities on the West coast of the United States, which is prone to Pacific Ocean Tsunamis, warning signs advise people where to run in the event of an incoming Tsunami. Computer models can roughly predict Tsunami arrival and impact based on information about the event that triggered it and the shape of the sea floor and the coastal landmass. One of the early warnings comes from nearby animals. Many animals sense danger and flee to higher ground before the water arrives. Monitoring their behaviour closely could provide advance warnings of earthquakes, Tsunamis etc.

In 2011, Earthquake Research Committee of Japanese Government announced that Tsunami forecasts would be started to alert the public in advance about the approaching Tsunamis in near future. This would comprise Tsunamic height, attack area and probability of occurrence within 100 years. Such forecasts should be soon activated in the Indian sub-continent also. The Intergovernmental Oceanographic Commission, UNESCO is working out strategies for this area.

Coastal areas of India are sitting on a ‘Tsunami-bomb’. Awareness and robust measures are the needs of the hour.

Tsunami Essay Word Meanings for Simple Understanding

• Seismic – pertaining to, of the nature of, or caused by an earthquake or vibration of the earth, Whether due to natural or artificial causes
• Pulverise – to demolish or crush completely
• Scouring – to clear or dig out (a channel, drain, etc) as by the force of water, by removing debris, etc
• Wavelength – the distance, measured in the direction of propagation of a wave, between two successive points in the wave that are characterised by the same phase of oscillation
• Recede – to go or move away, withdraw
• Oceanographer – the branch of physical geography dealing with the ocean
• Unscathed – not scathed, unharmed, uninjured
• Dissipate – to use up or waste, to disperse
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Essay on Tsunami

Students are often asked to write an essay on Tsunami in their schools and colleges. And if you’re also looking for the same, we have created 100-word, 250-word, and 500-word essays on the topic.

Let’s take a look…

100 Words Essay on Tsunami

What is a tsunami.

A tsunami is a series of powerful waves caused by the displacement of a large volume of water. This usually happens due to earthquakes, volcanic eruptions, or underwater landslides.

How Does a Tsunami Form?

When the sea floor abruptly deforms, it displaces the overlying water, triggering a tsunami. The waves travel across the ocean at high speeds.

Effects of a Tsunami

Tsunamis can cause mass destruction when they hit land. They can flood cities, destroy buildings, and take lives. It’s important to have early warning systems to minimize damage.

Understanding tsunamis helps us prepare and mitigate their harmful effects.

250 Words Essay on Tsunami

Introduction.

Tsunamis, deriving from the Japanese words ‘tsu’ meaning harbor and ‘nami’ meaning wave, are a series of powerful water waves caused by the displacement of a large volume of a body of water. They are known for their destructive power and unpredictability, posing a significant threat to coastal communities.

Causes of Tsunamis

Tsunamis are typically triggered by seismic activities beneath the ocean floor. These include earthquakes, volcanic eruptions, or landslides. The energy released during these events displaces the overlying water column, generating waves that can travel across oceans at high speeds.

Characteristics and Impact

Unlike regular waves, tsunami waves involve the movement of the entire water column from the sea surface to the seabed. This attribute contributes to their long wavelengths and high energy, enabling them to travel vast distances. Upon reaching shallow waters, their speed decreases, causing the wave height to increase dramatically, often resulting in widespread destruction when they hit land.

Prevention and Mitigation

While tsunamis cannot be prevented, their impact can be mitigated through early warning systems, coastal zone management, and community preparedness. Technological advancements have made it possible to detect seismic activities and issue timely alerts, thereby saving lives.

Tsunamis, while a fascinating natural phenomenon, are a stark reminder of nature’s power. Understanding their causes and characteristics is crucial in developing effective mitigation strategies, thereby reducing their devastating impacts on human lives and the environment.

500 Words Essay on Tsunami

Tsunamis, often referred to as seismic sea waves, are a series of ocean waves caused by any large-scale disturbance of the sea surface. These disturbances can include earthquakes, volcanic eruptions, landslides or even meteorite impacts in the ocean. Tsunamis are not regular sea waves but energy waves, often caused by seismic activities beneath the ocean floor. Their impact on human lives and the environment can be devastating, emphasizing the importance of understanding and predicting these natural disasters.

The Mechanics of a Tsunami

Tsunamis are initiated by a sudden displacement of the sea floor due to geological activities like earthquakes. This displacement results in a vertical shift of the overlying water column, creating a series of waves that radiate outwards from the point of origin. The speed of a tsunami is determined by the depth of water, with deeper waters facilitating faster wave speeds.

In the open ocean, these waves may be just a few centimeters high, but their wavelength, or the distance between successive crests, can span hundreds of kilometers. As these waves approach coastal areas, the shallowing sea floor compresses the wave energy, causing the wave to increase dramatically in height.

Impact and Consequences

The destructive power of a tsunami comes from the massive amount of water that it can move and the consequent flooding. When a tsunami reaches the shore, it can cause immense damage to structures, erode beaches and embankments, destroy vegetation, and severely impact both terrestrial and marine life.

Unfortunately, tsunamis cannot be prevented as they are triggered by natural geological processes. However, their impact can be mitigated through early warning systems, community preparedness, and intelligent coastal management.

Tsunami early warning systems, comprising seismographs and sea level monitoring stations, can provide critical minutes to hours of warning. This allows people in the path of a tsunami to seek higher ground. Community preparedness involves education about tsunami risks, evacuation routes, and drills. Intelligent coastal management can include the construction of seawalls, planting of mangroves to absorb wave energy, and zoning laws to prevent construction in high-risk areas.

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Find even more resources on tsunamis  in our searchable resource database.

Tsunamis are just long waves — really long waves. But what is a wave? Sound waves, radio waves, even “the wave” in a stadium all have something in common with the waves that move across oceans. It takes an external force to start a wave, like dropping a rock into a pond or waves blowing across the sea. In the case of tsunamis, the forces involved are large — and their effects can be correspondingly massive.

Expected tsunami wave heights from the March 2011 Honshu, Japan undersea earthquake. (Image credit: NOAA Center for Tsunami Research)

What is a tsunami?

A tsunami is a series of extremely long waves caused by a large and sudden displacement of the ocean, usually the result of an earthquake below or near the ocean floor. This force creates waves that radiate outward in all directions away from their source, sometimes crossing entire ocean basins. Unlike wind-driven waves, which only travel through the topmost layer of the ocean, tsunamis move through the entire water column, from the ocean floor to the ocean surface.

Imagine this: you are sitting on a beautiful beach enjoying a lovely day, when out of the blue an alarm blasts from your phone and reads “Tsunami warning.” Do you know where you would go and what to do? What if you aren’t in the U.S. and there are no alarms, would you know the signs of an approaching tsunami?

What causes tsunamis?

Most tsunamis are caused by earthquakes on converging tectonic plate boundaries . According to the Global Historical Tsunami Database , since 1900, over 80% of likely tsunamis were generated by earthquakes. However, tsunamis can also be caused by landslides, volcanic activity, certain types of weather , and—possibly—near-earth objects (e.g., asteroids, comets) colliding with or exploding above the ocean.

Tsunami movement

Once a tsunami forms, its speed depends on the depth of the ocean. In the deep ocean, a tsunami can move as fast as a jet plane, over 500 mph, and its wavelength , the distance from crest to crest, may be hundreds of miles. Mariners at sea will not normally notice a tsunami as it passes beneath them; in deep water, the top of the wave rarely reaches more than three feet higher than the ocean swell. NOAA Deep-ocean Assessment and Reporting of Tsunami (DART) systems, located in the deep ocean, are able to detect small changes in sea-level height and transmit this information to tsunami warning centers.

On the afternoon of April 13, 2018, a large wave of water surged across Lake Michigan and flooded the shores of the picturesque beach town of Ludington, Michigan, damaging homes and boat docks, and flooding intake pipes. Thanks to a local citizen’s photos and other data, NOAA scientists reconstructed the event in models and determined this was the first ever documented meteotsunami in the Great Lakes caused by an atmospheric inertia-gravity wave.

Tsunami safety

A tsunami only becomes hazardous when it approaches land. As a tsunami enters shallow water near coastal shorelines, it slows offsite link to 20 to 30 mph. The wavelength decreases, the height increases, and currents intensify.

Tsunami warnings come in different forms. There are official warnings issued by tsunami warning centers that are broadcast through local radio and television, wireless emergency alerts , NOAA Weather Radios, NOAA websites, and social media. They may also come through outdoor sirens, local officials, text message alerts, and telephone notifications. There may not be time to wait for an official warning, so it is important to be able to recognize natural tsunami warnings. These include strong or long earthquakes, a loud roar (like that of a train or an airplane) coming from the ocean, and a sudden rise or fall of the sea level that is not related to the tide. Official and natural warnings are equally important. Be prepared to respond immediately to any tsunami warnings. Move quickly to a safe place by following posted evacuation signs. If you do not see an evacuation route, go to high ground or as far inland as possible.

When they strike land, most tsunamis are less than 10 feet high, but in extreme cases, they can exceed 100 feet near their source. A tsunami may come onshore like a fast-rising flood or a wall of turbulent water, and a large tsunami can flood low-lying coastal areas more than a mile inland.

Rushing water from waves, floods, and rivers is incredibly powerful. Just six inches of fast-moving water can knock adults off their feet, and twelve inches can carry away a small car. Tsunamis can be particularly destructive because of their speed and volume. They are also dangerous as they return to the sea, carrying debris and people with them. The first wave in a tsunami may not be the last, the largest, or the most damaging. Stay out of the tsunami hazard zone until local officials tell you it is safe, as the danger may last for hours or days.

NOAA bathymetric data helps scientists more accurately model tsunami risk within Barry Arm

Tsunami effects on humans

Large tsunamis are significant threats to human health, property, infrastructure, resources, and economies. Effects can be long-lasting, and felt far beyond the coastline. Tsunamis typically cause the most severe damage and casualties near their source, where there is little time for warning. But large tsunamis can also reach distant shorelines, causing widespread damage. The 2004 Indian Ocean tsunami , for example, impacted 17 countries in Southeastern and Southern Asia and Eastern and Southern Africa.

Tsunami forecasting

Scientists cannot predict when and where the next tsunami will strike. But the tsunami warning centers know which earthquakes are likely to generate tsunamis and can issue messages when one is possible. They monitor networks of deep-ocean and coastal sea-level observation systems designed to detect tsunamis and use information from these networks to forecast coastal impacts and guide local decisions about evacuation. Tsunami warning capabilities have become dramatically better since the 2004 Indian Ocean tsunami. NOAA scientists are working to further improve warning center operations and to help communities be prepared to respond.

As Tonga’s Hunga Tonga-Hunga Ha'apai volcano began to erupt on January 15, 2022, it sent more than tsunami waves across the Pacific Ocean — some forms of communications in the region were sent into the dark, too. The eruption broke an underwater communications cable, leaving most of the island nation without internet access and other forms of communication.

EDUCATION CONNECTION

Students can investigate tsunamis to discover the impacts of Earth's systems on humans. Teachers can use these potentially deadly waves and other natural hazards to bring relevance to science concepts such as plate tectonics, acceleration and speed, force and motion, energy transfer, and the physics of waves . In addition, many schools, homes, and businesses are located in tsunami hazard zones offsite link . Many coastal states and territories have tsunami preparedness campaigns in place. Teaching students about tsunami safety and preparedness plans may ultimately save lives.

Essay on Tsunami For Students and Children

Table of Contents

Essay on Tsunami: A tsunami is a giant sea wave caused by underwater disturbances, like earthquakes, volcanic eruptions, or landslides. Tsunamis can travel at incredible speeds and devastate coastal areas. Preparedness and early warning systems are crucial for staying safe during tsunamis. In this blog, we will explore the concept of tsunamis and provide sample essays of various lengths (100, 200, 400, and 500 words) to help you understand the science behind tsunamis, their impact, and safety measures.

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Long and Short Essay on Tsunami

Whether you are looking for a short essay on tsunami of 100 words or a long essay of 500 words, we have got you covered. Here we have provided sample essays on tsunami with all the information that you need.

Sample Essay 1: Tsunami (100 Words)

Tsunamis, often called “harbor waves,” are colossal ocean waves caused by various natural events. The most common trigger is an underwater earthquake, which displaces a massive amount of water. This displacement creates a series of powerful waves that can travel across entire ocean basins.

When these waves reach shallower coastal regions, their energy compresses, causing the waves to grow in height. Tsunamis can appear as rapid, massive walls of water crashing ashore. They bring widespread destruction, flooding, and loss of life.

Tsunami early warning systems use seismic sensors and buoys to detect potential threats. When an earthquake occurs, these systems send alerts to coastal communities, allowing time for evacuation.

Sample Essay 2: Tsunami (200 Words)

Tsunamis are natural disasters characterized by colossal sea waves. These waves are triggered by a variety of underwater disturbances, the most common being undersea earthquakes. When the Earth’s crust shifts during a quake, it displaces a significant volume of water. This displaced water forms waves that radiate outward from the earthquake’s epicenter.

In the open ocean, tsunamis may go unnoticed because they are relatively low and have long wavelengths. However, as they approach shallower coastal areas, the waves grow in height and can reach towering proportions. Tsunamis can move at remarkable speeds, covering vast distances and striking coastal communities with little warning.

The impact of a tsunami can be catastrophic. As the powerful waves surge inland, they inundate low-lying areas, causing widespread flooding and property damage. Coastal infrastructure and buildings are particularly vulnerable. The immense force of tsunamis can uproot trees, vehicles, and anything in their path, leading to loss of life and injuries.

To mitigate the devastating effects of tsunamis, early warning systems have been developed. These systems use a network of seismic sensors and ocean buoys to detect underwater disturbances that could trigger a tsunami. When an event is detected, warnings are issued to coastal communities, giving them precious time to evacuate to higher ground and seek safety.

Sample Essay 3: Tsunami (400 Words)

A tsunami is a powerful natural disaster that can cause widespread devastation. It is a series of ocean waves that are generated by geological disturbances such as earthquakes, volcanic eruptions, or underwater landslides. These waves travel great distances across the ocean and can reach coastal areas with tremendous force, causing immense destruction. In this essay, we will explore the causes, effects, and precautionary measures associated with tsunamis.

Tsunamis are primarily caused by submarine earthquakes. When an earthquake occurs under the ocean, it can displace a large volume of water, creating a series of powerful waves. The strength and size of the waves are determined by factors such as the magnitude of the earthquake, the depth and location of its epicenter, and the characteristics of the seafloor. Volcanic eruptions and underwater landslides can also trigger tsunamis, although they are less common causes compared to earthquakes.

The effects of tsunamis can be devastating. As the waves approach the coast, their height increases, forming a wall of water that can reach heights of tens of meters. When these waves hit the shoreline, they can obliterate everything in their path, including buildings, infrastructure, and vegetation. The force of the waves can result in widespread flooding, with water infiltrating far inland. This can lead to the loss of human lives, displacement of populations, and destruction of entire communities. The economic and emotional toll of a tsunami can be immense and long-lasting.

Given the destructive potential of tsunamis, precautionary measures are crucial in order to minimize loss of life and property. Early warning systems, consisting of a network of sensors and communication systems, can detect the occurrence of an earthquake and subsequently issue a tsunami warning. This allows coastal populations to evacuate to higher ground or seek shelter in designated safe zones. Education and awareness campaigns are also important in order to educate people on how to respond to tsunami warnings and the importance of being prepared for such disasters.

In conclusion, tsunamis are a devastating natural disaster that can cause immense damage. They are primarily caused by submarine earthquakes but can also be triggered by volcanic eruptions or underwater landslides. The effects of tsunamis include widespread destruction, loss of life, and displacement of populations. Precautionary measures such as early warning systems and education campaigns are essential in minimizing the impact of tsunamis. It is important for coastal communities to be prepared and informed in order to mitigate the devastating consequences that tsunamis can bring.

Sample Essay 4: Tsunami (500 Words)

A tsunami is a tragic event that can cause immense destruction and loss of life. It is a series of ocean waves triggered by an underwater earthquake, volcanic eruption, or landslide. These waves can travel at incredible speeds across the ocean and reach massive heights when they make landfall. In this essay, we will explore the causes, effects, and preventive measures of tsunamis.

One of the primary causes of tsunamis is tectonic activity. When two tectonic plates beneath the Earth’s surface shift, it can result in an earthquake. If this earthquake occurs under the sea, it can displace a large volume of water, creating a tsunami. The magnitude of the earthquake determines the scale and intensity of the resulting tsunami. For instance, the 2004 Indian Ocean tsunami was caused by a massive earthquake with a magnitude of 9.1-9.3 off the coast of Sumatra.

The effects of a tsunami are devastating. As the waves travel towards the coast, they gain speed and height. When they finally crash onto the land, they can cause massive flooding and widespread destruction. Entire villages and cities can be wiped out in a matter of minutes. The force of the waves can also destroy infrastructure, such as homes, hospitals, and schools. The aftermath of a tsunami is filled with despair, as survivors struggle to recover and rebuild their lives.

Preventive measures are crucial to minimize the impact of tsunamis. Early warning systems play a pivotal role in alerting coastal communities about the imminent danger. These systems use buoys, seismographs, and satellites to detect and monitor earthquakes and other potential triggers of tsunamis. When a threat is detected, warnings are issued to the vulnerable areas, allowing people to evacuate to safer grounds. Additionally, coastal communities must have well-constructed infrastructure, such as sea walls and flood barriers, to minimize the impact of the waves.

Communities affected by tsunamis must also focus on building resilience. Education plays a crucial role in ensuring that residents are aware of the signs of a tsunami and know how to react in such situations. Regular drills and evacuation exercises can help prepare the population in case of a real event. It is also important to develop contingency plans that include emergency shelters, healthcare facilities, and systems to distribute food and supplies.

In conclusion, tsunamis are natural disasters that can cause immense devastation. They are triggered by underwater earthquakes, volcanic eruptions, or landslides. The impact of tsunamis includes widespread flooding, destruction of infrastructure, and loss of life. To prevent the devastating effects of tsunamis, early warning systems, well-constructed infrastructure, and education must be in place. With these preventive measures, we can better protect coastal communities and minimize the impact of this natural disaster.

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FAQs on Essay on Tsunami

What is a tsunami.

A tsunami is a giant sea wave caused by underwater disturbances, such as earthquakes, volcanic eruptions, or landslides.

How are tsunamis formed?

Tsunamis are typically formed when underwater earthquakes displace a massive volume of water, creating powerful waves that travel across the ocean.

What is the speed of a tsunami wave in the open ocean?

Tsunamis can travel at remarkable speeds in the open ocean, often exceeding 500 miles per hour (800 kilometers per hour).

What is tsunami short essay?

A tsunami is a massive sea wave caused by underwater disturbances like earthquakes, capable of devastating coastal areas. Early warning systems are crucial for tsunami preparedness.

What is tsunami in 150 words?

A tsunami is a natural disaster characterized by colossal ocean waves triggered by events such as underwater earthquakes, volcanic eruptions, or landslides. These waves can travel at incredible speeds across entire ocean basins. In the open ocean, tsunamis are relatively low and have long wavelengths, making them challenging to detect. However, as they approach shallower coastal regions, their energy compresses, causing them to grow in height dramatically. Tsunamis can cause widespread devastation when they reach the coast, flooding low-lying areas, destroying infrastructure, and posing a severe threat to human lives. Early warning systems equipped with seismic sensors and ocean buoys play a crucial role in detecting potential tsunami triggers and issuing timely alerts to coastal communities. Preparedness, awareness, and swift evacuation are key factors in minimizing the impact of tsunamis and saving lives.

What is tsunami in 10 lines?

A tsunami is a powerful natural event with colossal ocean waves. It's often triggered by underwater earthquakes, volcanic eruptions, or landslides. Tsunamis can travel at extraordinary speeds across the open ocean. In deep water, they may have long wavelengths and go unnoticed. As they approach shallower coastal regions, they grow in height. Tsunamis can cause widespread flooding, property damage, and loss of life. Early warning systems use seismic sensors and buoys to detect tsunamis. Alerts are issued to coastal communities, allowing time for evacuation. Preparedness and awareness are essential for tsunami safety. Swift action during a tsunami warning can save lives and reduce damage.

What is tsunami write brief?

A tsunami is a massive sea wave triggered by underwater events like earthquakes or volcanic eruptions. These waves can travel at high speeds across oceans and become dangerously large near coastlines. Tsunamis are known for their devastating impact, causing flooding, destruction of coastal infrastructure, and posing a significant threat to human lives. Early warning systems equipped with seismic sensors and ocean buoys help detect potential tsunamis and issue timely alerts to coastal communities. Preparedness and swift evacuation are critical for minimizing the impact of tsunamis and ensuring safety.

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• Forecast & Warning

The Tsunami Story

Tsunami is a set of ocean waves caused by any large, abrupt disturbance of the sea-surface. If the disturbance is close to the coastline, local tsunamis can demolish coastal communities within minutes. A very large disturbance can cause local devastation AND export tsunami destruction thousands of miles away. The word tsunami is a Japanese word, represented by two characters: tsu, meaning, "harbor", and nami meaning, "wave". Tsunamis rank high on the scale of natural disasters. Since 1850 alone, tsunamis have been responsible for the loss of over 420,000 lives and billions of dollars of damage to coastal structures and habitats. Most of these casualties were caused by local tsunamis that occur about once per year somewhere in the world. For example, the December 26, 2004, tsunami killed about 130,000 people close to the earthquake and about 58,000 people on distant shores. Predicting when and where the next tsunami will strike is currently impossible. Once the tsunami is generated, forecasting tsunami arrival and impact is possible through modeling and measurement technologies.

Generation. Tsunamis are most commonly generated by earthquakes in marine and coastal regions. Major tsunamis are produced by large (greater than 7 on the Richer scale), shallow focus (< 30km depth in the earth) earthquakes associated with the movement of oceanic and continental plates. They frequently occur in the Pacific, where dense oceanic plates slide under the lighter continental plates. When these plates fracture they provide a vertical movement of the seafloor that allows a quick and efficient transfer of energy from the solid earth to the ocean (try the animation in Figure 1). When a powerful earthquake (magnitude 9.3) struck the coastal region of Indonesia in 2004, the movement of the seafloor produced a tsunami in excess of 30 meters (100 feet) along the adjacent coastline killing more than 240,000 people. From this source the tsunami radiated outward and within 2 hours had claimed 58,000 lives in Thailand, Sri Lanka, and India.

Underwater landslides associated with smaller earthquakes are also capable of generating destructive tsunamis. The tsunami that devastated the northwestern coast of Papua New Guinea on July 17, 1998, was generated by an earthquake that registered 7.0 on the Richter scale that apparently triggered a large underwater landslide. Three waves measuring more than 7 meter high struck a 10-kilometer stretch of coastline within ten minutes of the earthquake/slump. Three coastal villages were swept completely clean by the deadly attack leaving nothing but sand and 2,200 people dead. Other large-scale disturbances of the sea -surface that can generate tsunamis are explosive volcanoes and asteroid impacts. The eruption of the volcano Krakatoa in the East Indies on Aug. 27, 1883 produced a 30-meter tsunami that killed over 36,000 people. In 1997, scientists discovered evidence of a 4km diameter asteroid that landed offshore of Chile approximately 2 million years ago that produced a huge tsunami that swept over portions of South America and Antarctica.

Figure 1. Click to see and animation of a tsunami generated by an earthquake.

Wave Propagation. Because earth movements associated with large earthquakes are thousand of square kilometers in area, any vertical movement of the seafloor immediately changes the sea-surface. The resulting tsunami propagates as a set of waves whose energy is concentrated at wavelengths corresponding to the earth movements (~100 km), at wave heights determined by vertical displacement (~1m), and at wave directions determined by the adjacent coastline geometry. Because each earthquake is unique, every tsunami has unique wavelengths, wave heights, and directionality (Figure 2 shows the propagation of the December 24, 2004 Sumatra tsunami.) From a tsunami warning perspective, this makes the problem of forecasting tsunamis in real time daunting.

Warning Systems. Since 1946, the tsunami warning system has provided warnings of potential tsunami danger in the pacific basin by monitoring earthquake activity and the passage of tsunami waves at tide gauges. However, neither seismometers nor coastal tide gauges provide data that allow accurate prediction of the impact of a tsunami at a particular coastal location. Monitoring earthquakes gives a good estimate of the potential for tsunami generation, based on earthquake size and location, but gives no direct information about the tsunami itself. Tide gauges in harbors provide direct measurements of the tsunami, but the tsunami is significantly altered by local bathymetry and harbor shapes, which severely limits their use in forecasting tsunami impact at other locations. Partly because of these data limitations, 15 of 20 tsunami warnings issued since 1946 were considered false alarms because the tsunami that arrived was too weak to cause damage.

Figure 2. Click to see the propagation of the December 24, 2004 Sumatra tsunami.

Forecasting impacts. Recently developed real-time, deep ocean tsunami detectors (Figure 3) will provide the data necessary to make tsunami forecasts. The November 17, 2003, Rat Is. tsunami in Alaska provided the most comprehensive test for the forecast methodology. The Mw 7.8 earthquake on the shelf near Rat Islands, Alaska, generated a tsunami that was detected by three tsunameters located along the Aleutian Trench-the first tsunami detection by the newly developed real-time tsunameter system. These real-time data combined with the model database (Figure 4) were then used to produce the real-time model tsunami forecast. For the first time, tsunami model predictions were obtained during the tsunami propagation, before the waves had reached many coastlines. The initial offshore forecast was obtained immediately after preliminary earthquake parameters (location and magnitude Ms = 7.5) became available from the West Coast/Alaska TWC (about 15-20 minutes after the earthquake). The model estimates provided expected tsunami time series at tsunameter locations. When the closest tsunameter recorded the first tsunami wave, about 80 minutes after the tsunami, the model predictions were compared with the deep-ocean data and the updated forecast was adjusted immediately. These offshore model scenarios were then used as input for the high-resolution inundation model for Hilo Bay. The model computed tsunami dynamics on several nested grids, with the highest spatial resolution of 30 meters inside the Hilo Bay (Figure 5). None of the tsunamis produced inundation at Hilo, but all of them recorded nearly half a meter (peak-to-trough) signal at Hilo gage. Model forecast predictions for this tide gage are compared with observed data in Figure 5. The comparison demonstrates that amplitudes, arrival time and periods of several first waves of the tsunami wave train were correctly forecasted. More tests are required to ensure that the inundation forecast will work for every likely-to-occur tsunami. When implemented, such forecast will be obtained even faster and would provide enough lead time for potential evacuation or warning cancellation for Hawaii and the U.S. West Coast.

Reduction of impact. The recent development of real-time deep ocean tsunami detectors and tsunami inundation models has given coastal communities the tools they need to reduce the impact of future tsunamis. If these tools are used in conjunction with a continuing educational program at the community level, at least 25% of the tsunami related deaths might be averted. By contrasting the casualties from the 1993 Sea of Japan tsunami with that of the 1998 Papua New Guinea tsunami, we can conclude that these tools work. For the Aonae, Japan case about 15% of the population at risk died from a tsunami that struck within 10 minutes of the earthquake because the population was educated about tsunamis, evacuation plans had been developed, and a warning was issued. For the Warapa, Papua New Guinea case about 40% of the at risk population died from a tsunami that arrived within 15 minutes of the earthquake because the population was not educated, no evacuation plan was available, and no warning system existed.

Eddie N. Bernard

References:

Bernard, E.N. (1998): Program aims to reduce impact of tsunamis on Pacific states. Eos Trans. AGU, 79(22), 258, 262-263.

Bernard, E.N. (1999): Tsunami. Natural Disaster Management, Tudor Rose, Leicester, England, 58-60.

Synolakis, C., P. Liu, G. Carrier, H. Yeh, Tsunamigenic Sea-Floor Deformations, Science, 278, 598-600, 1997.

Dudley, Walter C., and Min Lee (1998): Tsunami! Second Edition, University of Hawai'i Press, Honolulu, Hawaii.

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A tsunami is a catastrophic ocean wave, usually caused by a submarine earthquake , an underwater or coastal landslide , or a volcanic eruption. Waves radiate outward from the generating impulse at speeds of up to 500 miles (800 km) per hour, reaching maximum heights of 100 feet (30 metres) near coastal areas. Although often called tidal waves , the occurrence of tsunamis have no connection with tides. The word tsunami is Japanese for “harbour wave.”

Perhaps the most destructive tsunami in recorded history was the Indian Ocean Tsunami of 2004 . A 9.1-magnitude earthquake occurred off the coast of Sumatra in Indonesia. Waves as high as 30 feet (9 metres) struck the eastern coasts of India and Sri Lanka—some 750 miles (1,200 km) away—and traveled more than 1,800 miles (3,000 km) to East Africa. The final death toll was at least 225,000, mostly in Indonesia, Thailand, India, and Sri Lanka. The affected countries also reported extensive economic and infrastructural damage.

Because of frequent tsunamis in the Pacific Basin, many adjacent countries have established tsunami warning systems that look for large earthquakes (magnitude 7.0 or higher) and unusual changes in sea level. Depending on the distance from the seismic disturbance, this warning system may give people several hours to evacuate coastal areas.

Where is the safest place to go during a tsunami?

During a tsunami, experts recommend that people attempt to find higher ground that is as far inland as possible in order to avoid the deadly waves.

Can tsunamis occur on other planets?

Tsunamis are not limited to bodies of water on Earth. A 2016 analysis of the Martian surface revealed evidence of two separate tsunami events that occurred long ago, likely as a result of comet or asteroid impacts.

tsunami , catastrophic ocean wave , usually caused by a submarine earthquake , an underwater or coastal landslide , or a volcanic eruption. The term tidal wave is frequently used for such a wave, but it is a misnomer, for the wave has no connection with the tides.

After an earthquake or other generating impulse occurs, a train of simple, progressive oscillatory waves is propagated great distances over the ocean surface in ever-widening circles, much like the waves produced by a pebble falling into a shallow pool. In deep water a tsunami can travel as fast as 800 km (500 miles) per hour. The wavelengths are enormous, sometimes exceeding 500 km (about 310 miles), but the wave amplitudes (heights) are very small, only about 30 to 60 cm (1 to 2 feet). The waves’ periods (the lengths of time for successive crests or troughs to pass a single point) are very long, varying from five minutes to more than an hour. These long periods, coupled with the extremely low steepness and height of the waves, enables them to be completely obscured in deep water by normal wind waves and swell . A ship on the high seas experiences the passage of a tsunami as an insignificant rise and fall of only half a metre (1.6 feet), lasting from five minutes to an hour or more.

As the waves approach the coast of a continent , however, friction with the rising sea bottom reduces the velocity of the waves. As the velocity lessens, the wavelengths become shortened and the wave amplitudes (heights) increase. Coastal waters may rise as high as 30 metres (about 100 feet) above normal sea level in 10 to 15 minutes. The continental shelf waters begin to oscillate after the rise in sea level. Between three and five major oscillations generate most of the damage, frequently appearing as powerful “run-ups” of rushing water that uproot trees , pull buildings off their foundations, carry boats far inshore, and wash away entire beaches , peninsulas, and other low-lying coastal formations. Frequently the succeeding outflow of water is just as destructive as the run-up or even more so. In any case, oscillations may continue for several days until the ocean surface reaches equilibrium .

Much like any other water waves , tsunamis are reflected and refracted by the topography of the seafloor near shore and by the configuration of a coastline. As a result, their effects vary widely from place to place. Occasionally, the first arrival of a tsunami at a coast may be the trough of the wave, in which case the water recedes and exposes the shallow seafloor. Such an occurrence took place in the bay of Lisbon , Portugal, on November 1, 1755, after a large earthquake ; many curious people were attracted to the bay floor, and a large number of them were drowned by the wave crest that followed the trough only minutes later.

One of the most destructive tsunamis in antiquity took place in the eastern Mediterranean Sea on July 21, 365 ce . A fault slip in the subduction zone beneath the island of Crete produced an earthquake with an estimated magnitude of 8.0–8.5, which was powerful enough to raise parts of the western third of the island up to 10 metres (33 feet). The earthquake spawned a tsunami that claimed tens of thousands of lives and caused widespread damage throughout the Mediterranean, from islands in the Aegean Sea westward to the coast of present-day Spain . Tsunami waves pushed ships over harbour walls and onto the roofs of houses in Alexandria , Egypt , while also ruining nearby croplands by inundating them with salt water.

Perhaps the most destructive tsunami in recorded history took place on December 26, 2004, after an earthquake of magnitude 9.1 displaced the ocean floor off the Indonesian island of Sumatra . Two hours later, waves as high as 9 metres (30 feet) struck the eastern coasts of India and Sri Lanka , some 1,200 km (750 miles) away. Within seven hours of the quake, waves washed ashore on the Horn of Africa , more than 3,000 km (1,800 miles) away on the other side of the Indian Ocean . More than 200,000 people were killed, most of them on Sumatra but thousands of others in Thailand , India, and Sri Lanka and smaller numbers in Malaysia , Myanmar , Bangladesh , Maldives , Somalia , and other locations.

On March 11, 2011, seafloor displacement resulting from a magnitude-9.0 earthquake in the Japan Trench of the Pacific Ocean created a large tsunami that devastated much of the eastern coast of Japan ’s main island of Honshu . Waves measuring as much as 10 metres (33 feet) high struck the city of Sendai and other low-lying coastal regions of Miyagi prefecture as well as coastal areas in the prefectures of Iwate , Fukushima , Ibaraki , and Chiba . The tsunami also instigated a major nuclear accident at the Fukushima Daiichi power station along the coast.

One of the most notable prehistoric tsunamis took place during the K-T extinction , a global extinction event that eliminated approximately 80 percent of all animal species about 66 million years ago. Many scientists argue that the event was mostly caused by the impact of a large meteor or comet on the Yucatán Peninsula near Chicxulub, Mexico . The impact caused an enormous 1.6-km- (1-mile) tall tsunami that washed up on the shores of the Gulf of Mexico and the islands of the Caribbean before propagating across the Atlantic Ocean and other ocean basins .

Other tsunamis of note include those that followed the spectacular explosive eruption of the Krakatoa (Krakatau) volcano on August 26 and 27, 1883, and the Chile earthquake of 1960 . A series of blasts from Krakatoa submerged the island of Rakata between Sumatra and Java , creating waves as high as 35 metres (115 feet) in many East Indies localities, and killed more than 36,000 people. The largest earthquake ever recorded (magnitude 9.5) took place in 1960 off the coast of Chile , and it caused a tsunami that killed approximately 2,000 people in Chile, 61 people 15 hours later in Hawaii , and 122 people 22 hours later in Japan .

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What is a tsunami?

A tsunami is a series of waves caused by earthquakes or undersea volcanic eruptions..

On September 29, 2009, a tsunami caused substantial damage and loss of life in American Samoa, Samoa, and Tonga. The tsunami was generated by a large earthquake in the Southern Pacific Ocean.

Did you know?

Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea. Out in the depths of the ocean, tsunami waves do not dramatically increase in height. But as the waves travel inland, they build up to higher and higher heights as the depth of the ocean decreases. The speed of tsunami waves depends on ocean depth rather than the distance from the source of the wave. Tsunami waves may travel as fast as jet planes over deep waters, only slowing down when reaching shallow waters. While tsunamis are often referred to as tidal waves, this name is discouraged by oceanographers because tides have little to do with these giant waves.

More Information

Tsunami "Fast Draw" Animation

Tracking Tsunamis (Ocean Today Video)

National Weather Service TsunamiReady ™

NOAA Deep-ocean Assessment and Reporting of Tsunamis (DART)

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Damages of Tsunami to Human Beings Essay

1. Introduction A tsunami is a series of ocean waves with very long wavelengths (typically hundreds of kilometers) caused by large-scale disturbances of the ocean, such as earthquakes, volcanic eruptions, and landslides. When the sea floor is distorted, the water above is displaced. Displacement of water may also be caused by a sudden change in atmospheric pressure. Tsunamis are a Japanese term, which translates to "harbor wave." The reason why tsunamis are described like this is because when t ...

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Tsunamis 101

Find out how a tsunami is born ... and how it destroys.

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In Japanese, tsunami means "harbor wave." Tsunamis are ocean waves triggered by an earthquake , volcano, or other movement of the ocean floor. Potentially imperceptible in deep water, a tsunami increases in height as it encounters the shallow waters of shore, often leading to extensive wreckage and loss.

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Essay on Tsunami for Students in English | 500+ Words Essay

January 1, 2021 by Sandeep

Essay on Tsunami: A sudden, unexpected series of ocean waves of high risen wavelengths are called tsunami waves. They are strong currents of water waves that rush through inland spaces, flood nearby areas and last for a long time. They are seismic waves that trigger landslide undersea and force themselves through any obstacle on their way. Large volumes of water are displaced at great transoceanic distances at high speeds.

Essay on Tsunami 500 Words in English

Below we have provided Tsunami Essay in English, suitable for class 5, 6, 7, 8, 9 and 10.

A tsunami is a series of fierce waves generated by the displacement of water. They occur in substantial water bodies due to earthquakes, volcanic eruptions and underwater explosions. Tsunamis are also oftenly referred to as tidal waves. The waves are very high in magnitude as well as their length, and they can be immensely destructive.

Japan is the country which has recorded the most significant number of tsunamis. The tsunami generated in the Indian Ocean in the year 2004 is still considered as the most upsetting tsunami taking more than two hundred thousand lives. Tsunamis are quite rare in occurrence as compared to other natural disasters , but they are equally damaging.

Causes of Tsunami

The leading cause of a tsunami is attributable to an earthquake . However, even volcanic eruptions, landslides and comets or other heavenly bodies hitting the sea can be a source. When the tectonic plates of the earth positioned under the sea are disturbed, an earthquake takes place, causing the seawater to displace and erupt in sudden waves. These waves move further and further towards the shores. They can go unnoticed in the deep ocean but become more prominent as the water becomes shallow.

Landslides are another prominent cause of a tsunami. When heavy debris falls without warning with massive force into the sea, it causes a tremendous ripple effect. This ripple effect thus, causes tidal waves to form, which ultimately rise towards the land and cause massive destruction. During the eruption of a volcano on land, debris falls with a great thrust into the water body, causing the same ripple effect. Volcanoes can be underwater as well. They are known as submarine volcanoes. Tsunamis can further occur as a result of meteorological activity and human-made triggers.

Effects of Tsunami

When water washes away the shores with such colossal force, it damages the sewage system and freshwater. It also causes water fit for drinking to erode and contaminate. Because of the water being stagnant and polluted, numerous diseases like malaria affect a large number of people. They become ill, and infections spread quickly. A tsunami may even destroy nuclear plants which result in emittance of harmful radiations. These radiations are fatal to the health of every living organism. Mass evacuations become necessary in areas exposed to radiations because they can result in cancer, death and can even affect the DNA structures.

The saddest effect of a tsunami is the loss of lives in huge numbers. Tsunamis hit suddenly, with almost no warning and hence people get no time to escape it or run away. They drown, collapse, are electrocuted, etc. Tsunamis not only cause massive destruction of life but also degrade the environment in a gigantic way. It uproots trees and destroys pipelines which lead to the release of dioxides, raw sewage and other pollutants into the atmosphere. When these hazardous pollutants are washed into the sea, they also cause unbearable damage to the aquatic underwater life.

When the waves of a powerful tsunami smash the shores, they destroy trees, cars, buildings, telephone lines, pipelines and other man-made equipment into bits and pieces. Poverty rises in areas which get most affected by the wrath of tsunamis. The governments are also able to do little for their betterment immediately due to the high funding requirement and expenses.

Prevention of Tsunami

The government can invest in building strong and high protective infrastructure which can withstand the force of a tsunami. The length should be so tall, that the most upper wave of the tsunami cannot over top it. Also, heavy construction and livelihood activities in tsunami-prone areas can be avoided. The local authorities can install an efficient and fast early warning system. This would help to get all the people on alert. This way, more and more people would evacuate or leave the areas of danger, and human life destruction could be minimised.

Educating people and making them aware of the effects and impact of a tsunami is exceptionally crucial. They should be taught about the early warning signals of a tsunami and how to identify them. They should also learn how to be fully prepared in tough times like these instead of panicking and rapidly running around. Planting the coastal regions and boundaries with trees such as Mangroves which can absorb tidal wave energy can be another option. These can help to reduce the impact of a tsunami and curb the levels of destruction caused.

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• World Tsunami Awareness Day: Essay for Students in English

This is an essay on the topic "World Tsunami Awareness Day," a day that resonates with the profound force of Tsunamis and the collective effort to understand, prepare, and unite. Whether you're seeking to grasp the concept or preparing for school projects and competitions, this essay is a valuable resource that you can refer to anytime, anywhere.

Essay on “World Tsunami Awareness Day”

“ Title: Riding the Wave of Knowledge: World Tsunami Awareness Day

Each November 5th , the world unites to honor World Tsunami Awareness Day . We reflect on Tsunamis, nature’s most powerful and unpredictable force. This day is more than a calendar marker; it reminds us of nature’s might and the need to collaborate to prepare.

What is a Tsunami?

Tsunamis are like ocean giants, but not the friendly kind you see in cartoons. They are massive waves triggered by underwater earthquakes, volcanic eruptions, or landslides. These waves can travel across entire oceans and, when they reach the coast, they become towering walls of water, causing immense destruction.

November 5th: A Day of Remembrance

You might wonder, why November 5th? It’s not just a random date; it’s a day we remember as a significant event. Back in 1854, Japan experienced a massive Tsunami known as the Nanki Tsunami. This devastating wave caused a lot of damage and took many lives. This historical event is why the United Nations chose this date to raise awareness about Tsunamis.

Theme for 2023: “Fighting Inequality for a Resilient Future”

This year, World Tsunami Awareness Day has a special theme: " Fighting Inequality for a Resilient Future ." But what does that mean? It means that we want to ensure that everyone, no matter where they live or their background, has access to knowledge and resources to stay safe from Tsunamis. It's about being fair and making sure everyone has an equal chance to be prepared.

Real-Life Impact

Tsunamis are not just something we read about in books. They have destroyed many parts of the world. Take, for example, the Indian Ocean Tsunami in 2004. It was one of the deadliest Tsunamis in history, affecting 14 countries and taking the lives of over 230,000 people. This tragic event emphasized the need for a global early warning system, leading to the establishment of the Indian Ocean Tsunami Warning and Mitigation System.

Building Resilient Communities

So, what can we do about it? It's all about building resilient communities. Resilience means being able to bounce back from challenges and disasters. It involves creating plans, early warning systems, and knowing how to respond. For instance, Japan, a country frequently facing Tsunamis, has one of the most advanced Tsunami warning systems in the world. Their well-practiced evacuation plans have significantly reduced the impact of Tsunamis on their coastal communities.

The Role of Education

Education plays a vital role in raising awareness about Tsunamis. Many schools teach students about the science of Tsunamis, how to recognize warning signs, and what to do in case of a Tsunami. It's like having a superhero team to help us stay safe.

Conclusion for Essay

World Tsunami Awareness Day is not just another day on the calendar. It's a day of reflection and action. It reminds us of the incredible power of Tsunamis and the need to be prepared. So, let's come together, learn, and work towards building resilient communities that can face the unpredictable might of Tsunamis. As students, we have the power to make a difference by spreading the word and being ready.

World Tsunami Awareness Day serves as a beacon of awareness and preparedness in the face of nature's might. It's a global call to action, a moment of reflection, and a shared endeavor to build resilient communities. 

Whether you're looking to understand the concept or gearing up for school projects and competitions, remember that this essay is a reference you can turn to anytime, anywhere. As you ride the wave of knowledge, let's stand together in the face of this awe-inspiring natural force.

FAQs on World Tsunami Awareness Day: Essay for Students in English

1. How does a Tsunami affect human life?

Tsunamis can cause widespread loss of life, injury, and damage to property and infrastructure.

2. Where can I find an Essay on World Tsunami Day 2023?

You can find an essay on the “World Tsunami Awareness Day 2023” on Vedantu’s website.

3. Tsunami information in 150 words?

Tsunamis are giant waves that can be caused by earthquakes, volcanic eruptions, or landslides underwater. They can travel very fast, up to 500 miles per hour, and can be over 100 feet tall. Tsunamis can cause widespread damage and loss of life, so it is important to be prepared if you live in an area that is at risk.

4. What date is Tsunami Day celebrated?

The 5th of November is celebrated as World Tsunami Day.

5. From which language was the word Tsunami taken info?

Tsunami is a Japanese word. Tsu means port or harbor, and nami, means wave. 

99 Tsunami Essay Topic Ideas & Examples

🏆 best tsunami topic ideas & essay examples, 🥇 most interesting tsunami topics to write about, 📌 simple & easy tsunami essay titles, ❓ tsunami research questions.

• Impact of the Japan Tsunami 2011 Disaster on Tourism and Hospitality Industries Most coastal regions in the Pacific countries are highly populated due to the fact that the inland regions are usually mountainous and inhabitable compared to the relatively flatland in the coastal areas.
• Damages of Tsunami to Human Beings High Cost of Fighting Tsunami The total cost of tsunami could be billions of dollars since the damages of income generating business, and the cost used to curb the situation on the ground was quite […]
• The Japan Earthquake and Tsunami of 2011 Documentary The documentary reflects the events leading to the natural disasters and their aftermath, including an investigation into the reasons for the failure of the precautionary measures in place during the 2011 earthquake in Japan.
• The Indian Ocean Tsunami of 2004 and Its Consequences The worst effects of the great wave were observed in Indonesia, where the death toll exceeded 160,000 people, and the overall damages almost reached $4.
• 2011 Tsunami in Tohoku and Its Effects on Japan In this instance, the geological origin of the tsunami has to be discussed due to the fact that it plays a significant role in predicting the presence of a tsunami in the future.
• Tsunami Disasters in Okushiri Island In addition, fire outbreaks also contributed to the devastating effects of the tsunami. In addition, the question of educating and passing information about dangers of tsunami contributed to massive loss of lives.
• Tsunami: Definition and Causes Tsunamis have gained worldwide notoriety following the two devastating tsunamis that have occurred in the course of the last ten years. Submarine earthquakes can generate dangerous tsunamis and that the intensity of this tsunami is […]
• Natural Disasters: Earthquakes, Volcanoes, and Tsunamis In addition, the paper will outline some of the similarities and differences between tsunamis and floods. Similarities between tsunamis and floods: Both tsunamis and floods are natural disasters that cause destruction of properties and human […]
• Natural Disasters: Tsunami, Hurricanes and Earthquake The response time upon the prediction of a tsunami is minimal owing to the rapid fall and rise of the sea level.
• The Sumatra Earthquake of 26 December 2004: Indonesia Tsunami As such, the earthquake resulted in the development of a large tsunami off the Sumatran Coast that led to destruction of large cities in Indonesia.
• Causes and Effect of the Tsunami in Indonesia Scientifically tsunami is caused by the water which is impelled afar the interior of the underwater commotion, the change in this water levels move at the speed of about four hundred miles per sixty minutes […]
• Effect of the 2004 Tsunami on Indonesia The areas prone to tsunamis on the Indonesian coast are: The west coast of Sumatra, the south coast of Java, the north and south coasts of West Nusa, Tenggara and East Nusa Tenggara provinces, the […]
• Tsunami’s Reasons and Effects Therefore, it is essential to know how to anticipate the place and time of the occurrence of a tsunami and to determine which factors are the main in assessing the potential wave’s power and the […]
• South California Tsunami and Disaster Response This paper provides the report’s estimate figures in terms of human casualties and the structures affected by the wave. The Figure 1 represents the graphical representation of the data collected.
• Tsunamis: Case Studies Massive movement of seabed caused the tsunami during the earthquake movement. The Burma plates slipped around the earthquake’s epicenter.
• Tsunami Warning Systems In such a way, it is possible to conclude that the poor functioning of awareness systems in the past preconditioned the reconsideration of the approach to monitoring tsunamis and warning people about them.
• Tsunami and the Health Department The overstretching of health facilities poses a great challenge; how can the health department deal with tsunami cases to ensure that the community is disease-free and safe?
• Economic Tsunami and Current Economic Strategies The current economic situation in the world is the result of a great number of different factors including the sphere of finance.
• Tsunami Handling at a Nuclear Power Plant The information presented in this research paper has been analyzed and proved to be the actual content obtained by various parties that participate in the study of tsunamis.
• Tsunami Funding: On Assistance to the Victims of the December 2004 Tsunami In the US, through the help of the United Nations Organization in conjunction with the Red Cross, sited and established centers where people in the community would take their donations.
• Tsunami: Crisis Management The saving of lives during a disaster and emergency incident will depend on the proper coordination of the rescue team, delivery of the right skills to the scene which can only be achieved through the […]
• The Recommendations Made in the Field of Tsunami Emergency Managements Additionally, the tsunami that hit the coastal area of the Indian Ocean in 2004 was one of the events that led to reconsiderations of the preparedness levels in dealing with catastrophes of such scales.
• Tsunami Warning Management System Tsunami emergency management system detects and predicts tsunami in addition to warning individuals and government in good time before the onset of the disaster.
• Physical Aspect of Tsunami According to Nelson, wave length is the distance between similar points of the wave; the concepts of tsunami wave height and amplitude are interconnected, as the height is the distance between tsunami’s trough and peak, […]
• Tsunami Geological Origin Firstly, the source of the volcanic eruption has to be understood, as this natural phenomenon is one of the primary causes of a tsunami.
• Marketing after a Crisis: Recovering From the Tsunami in Thailand The researchers aim was to assess the damages caused by the tsunami, to evaluate and adjust the impact and strategize on how to combat the crisis in the future.
• What Is a Tsunami and What Causes Them? We shall dwell on the Shifts in the Tectonic plates as the reasoning behind the Tsunamis, but we have to understand the concept involved in the movement of the plate tectonics then how the earthquake […]
• The Impacts of Japan’s Earthquake, Tsunami on the World Economy The future prospects in regard to the tsunami and the world economy will be presented and application of the lessons learnt during the catastrophe in future” tsunami occurrence” management.
• Effect on People Who Have Been Through Tsunami The community and government were left with a major challenge of how to cope with the physical and psychological stress that was quite evident.
• Exceedance Probability for Various Magnitudes of Tsunami
• A Short History of Tsunami Research and Countermeasures in Japan
• New Computational Methods in Tsunami Science
• Adult Mortality Five Years After a Natural Disaster: Evidence From the Indian Ocean Tsunami
• Affect, Risk Perception and Future Optimism After the Tsunami Disaster
• Probabilistic Analysis of Tsunami Hazards
• Tsunami Risk Assessment in Indonesia
• Real-Time Tsunami Forecasting: Challenges and Solutions
• Battening Down the Hatches: How Should the Maritime Industries Weather the Financial Tsunami
• A Simple Model for Calculating Tsunami Flow Speed From Tsunami Deposits
• Implementation and Testing of the Method of Splitting Tsunami Model
• The Storegga Slides: Evidence From Eastern Scotland for a Possible Tsunami
• Coastal Vegetation Structures and Their Functions in Tsunami Protection: Experience of the Recent Indian Ocean Tsunami
• Tsunami Fragility: A New Measure to Identify Tsunami Damage
• Geological Indicators of Large Tsunami in Australia
• Calamity, Aid and Indirect Reciprocity: The Long Run Impact of Tsunami on Altruism
• Cash and In-Kind Food Aid Transfers: Tsunami Emergency Aid in Banda Aceh
• Confronting the “Second Wave of the Tsunami”: Stabilizing Communities in the Wake of Foreclosures
• A Numerical Model for the Transport of a Boulder by Tsunami
• Experimental Investigation of Tsunami Impact on Free Standing Structures
• Economic and Business Development in China After the Tsunami
• How Effective Were Mangroves as a Defence Against the Recent Tsunami?
• Estimating Probable Maximum Loss From a Cascadia Tsunami
• Faster Than Real Time Tsunami Warning With Associated Hazard Uncertainties
• Tsunami Science Before and Beyond Boxing Day 2004
• Sediment Effect on Tsunami Generation of the 1896 Sanriku Tsunami Earthquake
• Tsunami Generation by Horizontal Displacement of Ocean Bottom
• Joint Evaluation of the International Response to the Indian Ocean Tsunami
• The Effectiveness and Limit of Tsunami Control Forests
• Distinguishing Tsunami and Storm Deposits: An Example From Martinhal, SW Portugal
• Developing Effective Vegetation Bioshield for Tsunami Protection
• Indian Ocean Tsunami: Disaster, Generosity and Recovery
• Three-Dimensional Splay Fault Geometry and Implications for Tsunami Generation
• Assessing Tsunami Vulnerability, an Example From Herakleio, Crete
• Knowledge-Building Approach for Tsunami Impact Analysis Aided by Citizen Science
• Mental Health Problems Among Adults in Tsunami-Affected Areas in Southern Thailand
• Legitimacy, Accountability and Impression Management in NGOs: The Indian Ocean Tsunami
• Measuring Tsunami Preparedness in Coastal Washington, United States
• Standards, Criteria, and Procedures for NOAA Evaluation of Tsunami Numerical Models
• The Use of Scenarios to Evaluate the Tsunami Impact in Southern Italy
• Could a Large Tsunami Happen in the United States?
• What Does a Tsunami Look Like When It Reaches the Coast?
• Is It Rare for a Tsunami to Happen?
• What Happens to Sharks During a Tsunami?
• Where Is the Safest Place During a Tsunami?
• What’s the Worst Tsunami Ever?
• What Happens to the Beach Before a Tsunami?
• Why Does Water Go Out Before a Tsunami?
• Can You Survive a Tsunami With a Life Jacket?
• Where Do Tsunami Most Hit?
• How Are Tsunamis Different From Normal Ocean Waves?
• What Are the Designated Service Areas of the Tsunami Warning Centers?
• How Quickly Are Tsunami Messages Issued?
• What Is the Difference Between a Local and a Distant Tsunami?
• What Types of Earthquakes Generate Tsunamis?
• Can Near Earth Objects Generate Tsunamis?
• What Are the Causes of Tsunamis?
• How Can Tsunami Be Controlled?
• What Keeps a Tsunami Going?
• Which Country Has the Most Tsunamis?
• What Are Some of the Most Damaging Tsunamis to Affect the United States?
• What Is the Tsunami Hazard Level for Anchorage and the Upper Cook Inlet in Alaska?
• What Are Ways Tsunami Start?
• How Many Tsunami Happen a Year?
• Can a Boat at Sea Survive a Tsunami?
• What Happens to a Whale in a Tsunami?
• How Much Warning Is There Before a Tsunami?
• Tornado Topics
• Oceanography Research Ideas
• Volcano Research Topics
• Hurricane Topics
• Safety Essay Ideas
• Environmental Sustainability Essay Ideas
• Glaciers Topics
• Flood Essay Topics
• Chicago (A-D)
• Chicago (N-B)

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Tsunami Warning and Preparedness: An Assessment of the U.S. Tsunami Program and the Nation's Preparedness Efforts (2011)

Chapter: 1 introduction, chapter one introduction, the tsunami threat in the united states.

The 2004 Indian Ocean tsunami resulted in catastrophic losses of life and property and demonstrated how destructive tsunamis can be. More than 200,000 people died, with most occurring in Indonesia, which was near the tsunami source, but deaths were also reported in countries as far away as Somalia. Recently, the Samoan (September 2009) and Chilean (February 2010) tsunamis reminded the world of how quickly a tsunami can move onshore and destroy lives. In comparison to extreme weather—such as floods, hurricanes, or tornadoes—tsunamis have caused comparatively few fatalities in the United States over the past 200 years. Modern records kept since 1800 tally less than 800 lives lost due to tsunamis in the United States and territories. 1 In 1960, a magnitude 9.5 Chilean earthquake generated tsunami waves that killed 61 people and caused $24 million in property damage in Hilo, Hawaii (Eaton et al., 1961). The 1964 Good Friday earthquake in Alaska generated a tsunami that devastated local Alaskan communities and inundated distant communities as far south as Crescent City, California.

Earlier tsunamis—yet to be repeated in modern times—include tsunami waves of North American origin in the year 1700 that caused flooding and damage as far away as Japan. Paleo-records indicate that the Cascadia subduction zone off the Washington, Oregon, and northern California coasts has repeatedly generated potentially catastrophic tsunamis (Atwater et al., 2005). Because of the relative infrequency of catastrophic tsunamis in recent U.S. history, mobilizing the required resources to maintain the nation’s warning and preparedness capabilities is challenging.

Tsunamis are caused by a variety of geological processes, such as earthquakes, subaerial and submarine landslides, volcanic eruptions, or very rarely from meteorite impacts ( Box 1.1 ). However, it takes a large event (e.g., typically an earthquake of magnitude greater than 7.0) to generate a damaging tsunami. Therefore, determining the likelihood of future tsunamis for U.S. coastal communities requires an understanding of the likelihood of reoccurrence of such geological processes, the likely magnitude of such events, and the location of the sources (see Chapter 3 for additional details). Because most tsunamis result from earthquakes, the tsunami hazard is high along U.S. shores that adjoin boundaries between tectonic plates, particularly along the subduction zones of Alaska, the Pacific Northwest, the Caribbean, and the Marianas ( Figure 1.1 ). However, U.S. shores are also exposed to tsunamis generated far from them. For example, Hawaii has been struck by tsunamis that have been generated by earthquakes off the coasts of South America, Russia, and Alaska (Cox and Mink, 1963). Submarine landslides,

probably triggered by earthquakes, account for much of the known tsunami hazard along the U.S. Atlantic and Gulf coasts, and in southern California (Dunbar and Weaver, 2008). Seismically active faults and the potential for landslides in the Caribbean pose a significant tsunami risk for that region (Dunbar and Weaver, 2008).

Tsunami hazard zones of U.S. coastal communities contain thousands of residents, employees, and tourists, and represent significant economic components of these coastal communities (Wood, 2007; Wood et al., 2007; Wood and Soulard, 2008). The economic and social risks from tsunamis grow with increasing population density along the coasts. To reduce societal risks posed by tsunamis, the nation needs a clear understanding of the nature of the tsunami hazard (e.g., source, inundation area, speed of onset) and the societal characteristics of coastal communities (e.g., the number of people, buildings, infrastructure, and economic activities)

FIGURE 1.1 Global map of active volcanoes and plate tectonics illustrating the “Ring of Fire” and depicting subduction zones; both areas associated with frequent seismic activity. SOURCE: http://vulcan.wr.usgs.gov/Imgs/Gif/PlateTectonics/Maps/map_plate_tectonics_world_bw.gif; USGS .

that make them vulnerable to future tsunamis. With a clear understanding of the tsunami hazards and social vulnerability that comprise tsunami risk, officials and the general public can then prepare for future events and hopefully reduce this risk. 2

When assessing tsunami hazard and developing risk reduction measures, it is important to consider the distance between a coastal community and potential tsunami sources as well as the probability of occurrence. Near-field tsunamis (see Box 1.1 ) pose a greater threat to human life than far-field tsunamis because of the short time between generation and flooding; because the extent of flooding is likely greater; and because the flooded area may be reeling from an earthquake (National Science and Technology Council, 2005). Near-field tsunamis account for most U.S. tsunami deaths outside of Hawaii, but even Hawaii has suffered losses from near-field tsunamis. Because it takes a very large earthquake to impact the far-field, more triggering events have the potential to impact communities that are within an hour or less from the source. For example, an earthquake generated within the Cascadia fault zone along the northern California, Oregon, and Washington coasts will allow only minutes for evacuation of

the coastal communities after the earthquake is felt. In addition, tsunami observations demonstrate an increase in wave height with proximity to the source, resulting in extensive coastal flooding by a near-field tsunami. Consequences of a near-field tsunami are far greater for any given location.

Far-field tsunamis afford hours of advance notice for evacuation and are likely to have smaller wave heights than those in the tsunami’s near field. However, the farther a coastal community from the earthquake source the less likely it is to have felt the earthquake and the more dependent it is on an instrumental detection system to provide warnings. Timely and accurate warnings are required to implement orderly evacuations and to avoid frequent unnecessary evacuations, which can be costly. The National Science and Technology Council (NSTC) report (2005) concludes that “the challenge is to design a tsunami hazard mitigation program to protect life and property from two very different types of tsunami events.”

GOALS AND SCOPE OF THIS REPORT

The 2004 Indian Ocean tsunami, spurred two congressional acts intended to reduce losses of life and property from future tsunamis. The Emergency Supplemental Appropriations Act for Defense, the Global War on Terror, and Tsunami Relief, 2005 (P.L. 109-13), included $24 million to improve tsunami warnings by expanding tsunami detection and earthquake monitoring capabilities. This Act was followed in 2006 by the Tsunami Warning and Education Act (P.L. 109-424), which directs the National Oceanic and Atmospheric Administration (NOAA) to strengthen the nation’s tsunami warning system (TWS), work with federal and state partners toward the mitigation of tsunami hazards, establish and maintain a tsunami research program, and assist with efforts to provide tsunami warnings and tsunami education overseas.

Section 4(j) of the Tsunami Warning and Education Act calls upon the National Academy of Sciences (NAS) “to review the tsunami detection, forecast, and warning program established under this Act to assess further modernization and coverage needs, as well as long-term operational reliability issues.” In response, NOAA asked the NAS to assess options to improve all aspects of the tsunami program. This request is reflected in the first part of the committee’s charge (see Appendix B ) and accordingly focuses on efforts on tsunami detection, forecasting, and warning dissemination.

The NAS, in accepting this charge and in consultation with NOAA, broadened the review’s scope to include an assessment of progress toward additional preparedness efforts to reduce loss of life and property from tsunamis in the United States as part of the National Tsunami Hazard Mitigation Program (NTHMP). The main rationale for this broadened scope was to address Section 5(a) in P.L. 109-424, which called for “a community-based tsunami hazard mitigation program to improve tsunami preparedness of at-risk areas in the United States and its territories.” Such a tsunami hazard mitigation program requires partnership among federal, state, tribal, and local governments. Its strategies include identifying and defining tsunami hazards, making inventories of the people and property in tsunami hazard zones, and providing the public with knowledge and infrastructure for evacuation, particularly for near-field

tsunamis that come ashore in a few minutes. The broadened scope aims at encompassing the range of national tsunami warning and preparedness efforts.

The Range of Options Available for Tsunami Hazard Mitigation

As the scope of the study was broadened to include aspects of tsunami hazard mitigation, the committee recognized the need to define the term “mitigation” and set some boundaries for the study, because the full suite of mitigation options exceeds the purview and capacity of this particular study. The definition of hazard mitigation and the actions it includes differ among various hazard communities. Some members of the academic community consider the full range of hazard mitigation options to include three classes of actions (White and Haas, 1975): (1) modifying the natural causes of hazards, (2) modifying society’s vulnerability (e.g., levees, wind- and seismic-resistant houses), and (3) redistributing the losses that occur (e.g., insurance, emergency response). In contrast, natural hazard practitioners consider the range of human adjustment to natural hazards to fall into two major classes of actions: (1) mitigation of potential losses through interventions in the constructed world in ways that lessen potential losses from nature’s extremes (e.g., land-use management, control and protection works, building codes), and (2) preparedness for, response to, and recovery from specific events and their associated losses (Mileti, 1999).

Focus on Warning and Preparedness

Although land-use planning and adjusting building codes is important in mitigating the impacts of tsunamis, the charge to the committee is focused primarily on the detection, forecast, and warning for near- and far-field tsunamis and issues directly related to the effective implementation of those warnings. To be responsive to its charge, the report focuses on the second class of mitigation actions, which generally includes pre-event planning to develop preparedness plans, appropriate organizational arrangements, training and exercises for issuing event-specific public warnings, an adequate emergency response, and plans for recovery and reconstruction. These types of adjustment are based on the notion that the adequacy of pre-event planning determines the effectiveness of event-specific response. This view also places insurance in the preparedness class.

THE NATION’S TSUNAMI WARNING AND PREPAREDNESS EFFORTS

Only very recently has there been a national interest in tsunami warning and preparedness. Before 2004, most efforts were spearheaded by local, state, or regional initiative operating on very limited budgets. Integrating these existing individual efforts into a national tsunami program has led to a very different type of program than that of a national tsunami warning program designed from the outset. The history of tsunami warning and preparedness efforts can be traced back to two of the six destructive tsunamis that caused causalities on U.S. soil.

These efforts were originally part of the National Geodetic Survey, which developed the two tsunami warning centers (TWCs) in Hawaii and Alaska after the 1946 Aleutian tsunami (Unimak Island, AK) and the 1964 Alaskan tsunami (Prince William Sound, AK) ( Figure 1.2 ). These centers eventually became part of NOAA’s National Weather Service (NWS), but each is located in different NWS regions and is managed independently.

Concern about tsunamis in Washington, Oregon, and California increased in the late 1980s and early 1990s when several new scientific studies revealed their near-field tsunami threat from the Cascadia subduction zone (Atwater, 1987; Heaton and Hartzell, 1987). California was reminded of its potential tsunami threat by an earthquake near Cape Mendocino in 1992, which generated a small tsunami that arrived in Eureka only minutes after the earthquake occurred. These and other developments prompted a more urgent call to produce comprehensive assessments of tsunami risk and preparedness at the state and federal level.

Congress responded to this call in a 1995 Senate Appropriations Committee request to NOAA to develop a plan for reducing tsunami risk to coastal communities. NOAA suggested the formation of a national committee to address tsunami threat, leading to the establishment of the NTHMP that same year. The NTHMP is tasked with coordinating the various federal, state, territorial, and commonwealth tsunami efforts. NOAA’s Tsunami Program was established in 2005 to incorporate all the current tsunami efforts at NOAA (see below). To respond to the committee’s charge (see Appendix B ) and assess progress made toward improved tsunami warning and preparedness, the committee begins its evaluation with an inventory of the elements of the NTHMP and NOAA’s Tsunami Program.

National Tsunami Hazard Mitigation Program

The NTHMP has a Coordinating Committee (steering committee) that works to collaborate on the tsunami mitigation efforts of the NTHMP and three subcommittees: a Mapping and Modeling Subcommittee, a Warning Coordination Subcommittee, and a Mitigation and Education Subcommittee. 3 In addition to coordinating individual efforts, the NTHMP provides guidance to NOAA’s TWSs. Federal partners include NOAA, the U.S. Geological Survey (USGS), and the Federal Emergency Management Agency (FEMA). State partners originally included Hawaii, Alaska, Washington, Oregon, and California, and now include all 29 U.S. coastal states and territories.

The USGS contributes to the seismic network that the TWCs use through operating and maintaining their respective seismic networks and to the tsunami research and risk assessments and conducts an independent seismic analysis of potential tsunamigenic earthquakes at its National Earthquake Information Center (NEIC). The USGS and NOAA both support the Global Seismographic Network (GSN), which provides high-quality seismic data to assist earthquake detection (including tsunamigenic earthquakes). Both agencies also support earthquake and seismic studies to improve tsunami warning efforts and tsunami disaster response and hazards assessments. FEMA is responsible for hazard mitigation and emergency response; as

FIGURE 1.2 Timelines for U.S. tsunami warning centers, programs, tsunami budget, deaths from tsunamis in the United States and its territories, and earthquakes of magnitude 8.0 or larger worldwide since the year 1900. Sources of data for this figure include: NOAA (federal spending); http://www.ngdc.noaa.gov/hazard/tsu_db.shtml (tsunami fatalities); http://earthquake.usgs.gov/earthquakes/eqarchives/ (great earthquake history). SOURCE: Committee member.

part of its mitigation efforts it has issued Guidelines for Design of Structures for Vertical Evacuation from Tsunamis (Federal Emergency Management Agency, 2008). FEMA becomes the lead federal agency in managing the emergency response once a tsunami has caused damage to U.S. coastlines.

The National Science Foundation (NSF) used to be a partner of the NTHMP, but as its involvement decreased the decision was made in 2009 to remove it from the NTHMP. Its primary function is to provide research funding and to partner with other federal agencies in research and development. NSF provides funding for the GSN. NSF has also been actively involved with investments regarding tsunami research infrastructure, such as the Network for Earthquake and Engineering Simulation (NEES), Earthquake Engineering and Research Centers (EERCs), and the Southern California Earthquake Center (SCEC) (Bement, 2005). Because it is not part of the NTHMP and its funding decisions are primarily driven by the demand in the research community, this report does not include an explicit discussion of NSF’s role but rather discusses the role of the broader research community in the nation’s tsunami efforts.

NOAA has been carrying most of the responsibility and obtains most of the funding to provide tsunami warnings, maintain observing networks (including seismic networks not funded by the USGS in Alaska and Hawaii), manage and archive data, and conduct research (further discussed in the next section).

The coastal states, U.S. territories, and commonwealths contribute their own initiatives and resources to the nation’s preparedness and education efforts; these vary in extent and approach from state to state. In particular, states are responsible for providing communities with inundation maps that allow municipalities to produce evacuation maps and guidance, and to educate the public about the hazard and appropriate responses. Local officials in turn are responsible for transmitting tsunami alerts throughout their respective jurisdictions, issuing evacuation orders, managing evacuations, and declaring all-clears.

NOAA’s Tsunami Program

In 2006, the Tsunami Warning and Education Act (P.L. 109-424) charged NOAA with addressing the nation’s priorities in tsunami detection, warning, and mitigation. NOAA’s Tsunami Program assumed the responsibilities to plan and execute NOAA’s tsunami efforts, primarily the program’s budget, strategic plan, and the coordination of activities among its NOAA organizational components and external partners, including the NTHMP. NOAA’s Tsunami Program advocates an end-to-end TWS, which includes detection, warnings and forecasts, message dissemination, outreach and education, and research.

NOAA’s Tsunami Program is supported by five line offices ( Table 1.1 ): NWS; the Office of Marine and Aviation Offices (OMAO); the National Ocean Service (NOS); Oceanic and Atmospheric Research (OAR); and the National Environmental Satellite, Data, and Information Service (NESDIS). The NWS, as the administrator for NOAA’s Tsunami Program, is primarily responsible for helping community leaders and emergency managers in strengthening their local tsunami

TABLE 1.1 Tsunami Program Matrix

warning and preparedness programs through its TsunamiReady program as well as operating the TWCs.

The Pacific Region’s Pacific Tsunami Warning Center (PTWC) and the Alaska Region’s West Coast/Alaska Tsunami Warning Center (WC/ATWC) are administered within the NWS, although the two TWCs report to their respective regional NWS offices. The two TWCs have distinct areas of responsibility as described in Chapter 5 . The NWS also houses the National Data Buoy Center (NDBC), which operates and maintains the Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys. These buoys monitor and alert the TWCs of sea level changes associated with a tsunami. OMAO collaborates by providing detection system maintenance support and conducting coastal surveys. NOS provides state and local coastal emergency managers with hazard-related information such as training and assessment tools, and also operates coastal tide stations and sea level gauges that monitor changes in sea level. OAR comprises a research network involving internal research laboratories, grant programs, and collaborative efforts between NOAA and academic institutions. Pacific Marine Environmentla Laboratory (PMEL), within OAR, focuses on designing optimal tsunami monitoring networks, improving forecast modeling, and improving impact assessment on coastal communities. NESDIS provides access to global environmental data; such as climate, geophysical, and oceanographic data. The National Geophysical Data Center (NGDC), housed within NESDIS, manages a database for historic tsunami events, maps, and DART and tide gauge records. Some negative consequences arising from this distribution of tsunami detection, forecast, warning, and planning functions across different parts of NOAA and across different NTHMP partners is discussed in greater detail in Chapters 3 and 5 .

ASSESSING THE NATION’S EFFORTS

Because tsunami warning and preparedness efforts are distributed across federal and state agencies and were historically conducted without a federal coordination mechanism, the committee faced a number of challenges in assessing progress in the nation’s ability to warn and prepare for the threat of tsunamis. The first challenge results from the need to assess many individual activities. Secondly, it is difficult to extrapolate from these individual activities to assess whether all the distributed efforts can function coherently during a tsunami to warn and evacuate people in a timely fashion. To help address these challenges, the committee began its analysis by sketching the required functions and elements of an idealized integrated warning and preparedness effort based on available research findings in the hazards and high-reliability organizations (HRO) literature (see section below). The committee then sought to compare its vision of an idealized system with the evolving status quo.

An ideal integrated TWS comprises multiple technologies, systems, individuals, and organizations. A comprehensive view of the elements therefore includes technical, organizational, social, and human components. The ideal system incorporates risk assessment, public education, tsunami detection, warning management, and public response ( Figure 1.3 ).

Protecting and warning the public begins with an understanding of the tsunami risk envi-

FIGURE 1.3 Components of an integrated warning system: Risk assessment includes all assessments required to effectively plan evacuations (including tsunami source determination, inundation modeling, and evacuation mapping) and prepare the communities to evacuate in the event a warning is issued or received. Risk assessments identify needs for public education. Public education aims to ensure maximum preparedness and a public that knows what to do when it receives a warning or feels the ground shaking in the case of near-field tsunamis. Threat detection comprises the continuous monitoring of the natural and technological environments that could create an emergency; it informs the warning management and public response component using threshold criteria and communication technology. Warning management interfaces the threat detection component with the public response component and is responsible for tsunami alerts, warnings, and evacuations; in consultation with the threat detection component it will alert and warn the public. Public response is the ultimate outcome of the integrated warning system, and it integrates public education, threat detection, natural cues from tsunami triggers, and warning management. SOURCE: Committee member; design by Jennifer Matthews, University of California, San Diego.

ronment. This must be done before a tsunami is generated in order to design the threat detection system, the education and awareness campaigns, and the evacuation and response plans. To understand the risk environment, both hazards (the physical characteristics of tsunamis and the inundation area) and vulnerabilities (the people and properties in harm’s way) need to be characterized (National Research Council, 2006). Pre-event public education is required to enable at-risk populations to correctly interpret: (1) natural cues from the environment (e.g., ground shaking from the earthquake) or (2) warnings from a technical detection system as a signal to evacuate to higher ground in a timely fashion. The threat detection component monitors the environment for threshold events using cues from natural and technical systems (Mileti, 1999; Mileti and Sorenson, 1990).

Once a significant tsunami is detected, the warning process needs to be managed. Tsunami information needs to be analyzed and decisions have to be made about the extent of the warning. Managers and decision makers issue warnings directly to the public. Ideally, officials managing the response also maintain situational awareness and information flow between the technical detection system and the public to update warnings and messages with the required protective actions to be taken. Because of the dominance of real-time communications, the Internet, and social networking, both the general public and media will increasingly access tsunami information directly from real-time information sources (e.g., the TWCs, seismometers, and water-level gauges) before local officials are able to respond. The public’s real-time access to different information sources, such as social media and networking systems, underscores the importance of public education to prepare both the public and the press for proper interpretation of information and response to detected hazards. An effective warning system monitors the public’s response and reactions in order to improve its processes for effective, understandable, actionable, reliable, and accurate warnings of impending danger. In the following chapters, the report covers the system components and compares the idealized system with current and/or planned efforts.

An integrated TWS has an impact on large populations and on a wide range of resources and, in the event of failure, has the potential to cause enormous economic, social, organizational, technological, and political losses. Although often seen as mainly comprising technical and technological elements, a warning system must, out of necessity, include the human dimension, such as people’s behavior, policies, procedures, and organizations. However, it is the human dimension that poses a significant challenge:

This involves the setting and running of national services (people), and the implementation of complex emergency-preparedness and awareness plans at the national and local levels to immediately inform every person of the threat. In the building of any early warning system, this is the difficult part. (Intergovernmental Oceanographic Commission, International Strategy for Disaster Reduction, and World Meteorological Organization, 2005).

CHALLENGES TO REDUCING THE NATION’S VULNERABILITY TO TSUNAMIS

Reducing the vulnerability of coastal settlements and infrastructure to tsunami risk poses some unique challenges. Although tsunamis can be devastating, as was seen during the 2004 Indian Ocean event, catastrophic tsunamis are relatively infrequent. This infrequency makes it more challenging to sustain the capacity to educate, warn, and prepare for this particular hazard. As discussed above, the history of tsunami warning and mitigation efforts in the United States shows that significant new funding is often made available only after a tsunami has devastated a coastal community and caused casualties. High funding levels and commitment to tsunami mitigation dissipate over time, leading to difficulties in maintaining efforts, knowledge, and lessons learned over time. Another challenge is the need to relay warnings from the fed-

eral government to state and local officials in just minutes (in the case of a near-field tsunami) or hours (in the case of a far-field tsunami). Sustaining the organizational preparedness and coordination across many jurisdictional boundaries presents a daunting challenge.

The committee recognizes that the nation’s tsunami detection, warning, and preparedness efforts originated in many diverse efforts distributed across several coastal states, and that attempts to integrate these distributed components into a coherent program have only recently begun. In particular, because tsunamis are rapid onset events, there is very little margin for error in the system before failure becomes catastrophic. An organization that operates in a low probability, high-risk environment, allowing few errors, is called an HRO (Roberts, 1990). HROs manifest a number of common properties: flexible and adaptable organizational structures, continually reinforced organizational learning, decision making that is both flexible and mobile, a strongly reinforced organizational culture, constant and effective communication, and trust among members of the system, particularly across organizations (Grabowski and Roberts, 1999; Grabowski et al., 2007). Because the committee identified the need for high-reliability operations in TWSs, the committee draws from the research literature on HROs (Roberts, 1990) and resilient systems (Hollnagel et al., 2008) to highlight particular characteristics that reduce the risks of failure in an idealized end-to-end warning system:

Situational Awareness in an Emergency: Because tsunamis are events that allow only minutes to hours for evacuation, a keen sense of situational awareness and the ability to respond quickly and effectively is required (Weick, 1990, 1993, 2003). HROs require decision making that is adaptable to change and surprise, and that is able to continually reassess needs across distributed organizations (Weick, 1993, 1998; Weick et al., 1999). Such is the case with the nation’s tsunami warning and preparedness efforts, where the TWCs, the state and local offices, and emergency managers and the affected public are geographically dispersed and often lack face-to-face contact. The dispersed and decentralized nature of the end-to-end tsunami warning and preparedness efforts make it a significant challenge to maintain awareness of the evolving situation during a crisis.

Learning and Training: To maintain situational awareness under changing conditions requires training. Therefore, an effective TWS requires that watchstanders, emergency managers, regulators, the public, and the media learn together, and engage in learning that enhances sense-making and developing alertness to small incidents that may cascade into much larger disasters (Weick, 1993; Farber et al., 2006). Because of the low frequency of tsunamis (e.g., California is issued an alert bulletin on average once every three years; Dengler, 2009), a TWS has few opportunities to learn from an event and therefore needs to learn from exercising the system through drills. Trial and error can be disastrous not only because disasters are rare, but also because in the absence of a major catastrophe to focus attention in the system, lessons learned from previous events may be forgotten or misapplied (March et al., 1991; Levitt and March, 1988; De Holan and Phillips, 2004). Learning in a high-reliability organization needs to be systematic, continually reinforced, measured, and made part of the system’s core values.

Fluid Organizational Structures: HRO structures are often adaptable and fluid, allowing the system to expand or contract in response to its environment (Roberts, 1990). TWSs with flexible organizational structures would be able to expand and contract resources in response to shifts and changes in environmental demands, disasters, or periods of slack resources. In the event of a tsunami, TWS managers need to grow effective, functioning response organizations in a period of less than 24 hours, and then adjust the organizational structures to the needs of the response (Tuler, 1988; Bigley and Roberts, 2001). The ability to provide varied organizational structures in response to environmental demands may be critical to the success of TWS organizations, similar to the way fire and emergency organizations expand and contract in response to fire demands (Grabowski and Roberts, 1999). Distributed information technology that connects the system responders can provide the technological glue that ties HRO members together, and fluid organizational structures can allow the organization to grow, expand, contract, and respond to changes in a dynamic, high tempo environment (Bigley and Roberts, 2001). Similar requirements for members and organizations in TWSs can be envisioned as tsunami conditions unfold.

Strong Organizational Culture: Schein (1992, 1996) defines “culture” as a set of basic tacit assumptions, that a group of people share, about how the world is and ought to be; it determines their perceptions, thoughts, feelings, and to some degree, their overt behavior. In many organizations, shared assumptions typically form around the functional units of the organization and are often based on members’ similar educational backgrounds or experiences (Grabowski and Roberts, 1996, 1997). HROs are characterized by strong cultures and norms that reinforce the organization’s mission and goals and that focus attention on procedures, policies, and reward structures consistent with the organization’s mission and safety (LaPorte and Consolini, 1991). HROs have cultures attentive to errors; cultures where closely held ideas about the organization, its mission, and member roles in reliability enhancement are articulated; cultures that encourage learning; and cultures where safe areas—for decision making, communication, and the like—are created as buffers (Weick, 1993). Constructs such as oversight and checks and balances reinforce the strong cultural norms of the HRO. Melding the varied cultures that integrate the system into a cohesive whole can be extremely difficult in distributed systems that are connected by linkages that can dissolve and wane as requirements, organizational structures, and political will change (Weick, 1987; Weick and Roberts, 1993; Grabowski and Roberts, 1999).

Managing decision making across organizations that report to different management structures is a challenge for highly dispersed efforts; this is certainly the case with U.S. tsunami detection, warning, and preparedness efforts. A particular challenge is that the federal government has responsibility to forecast and warn about potential hazards, yet local governments order evacuations. Failure to consider distributed decision making within groups and across multiple units can lead to lack of readiness for the next large-scale catastrophe; e.g., Hurricane Katrina (Roberts et al., 2005; Farber et al., 2006). Building good communication and trust aid in

effective decision making and can increase the likelihood of success in geographically dis-tributed organizations. Trust can be built by common training; opportunities for scientific and operational exchange; and workshops, conferences, exercises, and simulations that build community and coherence across distributed organizations.

TYING IT ALL TOGETHER: REPORT ROADMAP

In the following chapters, the committee assesses progress in the nation’s distributed tsunami preparedness, detection, and warning efforts and compares it to its vision of an idealized warning system ( Figure 1.3 ). Chapter 2 evaluates progress in hazard and vulnerability assessments and identifies potential improvements that could guide the nation’s tsunami risk-assessment efforts. Chapter 3 discusses education and outreach efforts and evaluates pre-event community and organizational preparedness and the coordination between the various entities at the local, state, and federal levels. Chapter 4 examines the technical hazard detection system, including the seismic and sea level sensor networks. Chapter 5 examines the TWCs’ operations and how technology and human capital are used to provide their functions. Appendices present supporting data on tsunami sources, hazard and evacuation maps, educational efforts, seismological methods, and several case-study tsunamis.

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Many coastal areas of the United States are at risk for tsunamis. After the catastrophic 2004 tsunami in the Indian Ocean, legislation was passed to expand U.S. tsunami warning capabilities. Since then, the nation has made progress in several related areas on both the federal and state levels. At the federal level, NOAA has improved the ability to detect and forecast tsunamis by expanding the sensor network. Other federal and state activities to increase tsunami safety include: improvements to tsunami hazard and evacuation maps for many coastal communities; vulnerability assessments of some coastal populations in several states; and new efforts to increase public awareness of the hazard and how to respond.

Tsunami Warning and Preparedness explores the advances made in tsunami detection and preparedness, and identifies the challenges that still remain. The book describes areas of research and development that would improve tsunami education, preparation, and detection, especially with tsunamis that arrive less than an hour after the triggering event. It asserts that seamless coordination between the two Tsunami Warning Centers and clear communications to local officials and the public could create a timely and effective response to coastal communities facing a pending tsuanami.

According to Tsunami Warning and Preparedness , minimizing future losses to the nation from tsunamis requires persistent progress across the broad spectrum of efforts including: risk assessment, public education, government coordination, detection and forecasting, and warning-center operations. The book also suggests designing effective interagency exercises, using professional emergency-management standards to prepare communities, and prioritizing funding based on tsunami risk.

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