IX Международный конкурс научно-исследовательских и творческих работ учащихся
Старт в науке
Цунами, как одно из стихийных бедствий, которое можно предотвратить
Автор работы награжден дипломом победителя II степени
Полная версия работы доступна во вкладке "Файлы работы" в формате PDF
Introduction
«A silent tsunami which knows no borders is sweeping the world. »
Josette Sheeran
Look at the view outside the window. The ground looks as if it is standing quite still, does not it? But it is not. Our world is spinning round and round, like a huge top. We have focused attention to the fact that when we look at this beauty, our mood rises. The world around us is full of unexpected things. Unfortunately, the man can not understand all of them. Instead of living in harmony with nature, human beings attempt to improve their laws and the way on the Earth.
People choose disregarding and ignoring for the sake of their own immediate gain but the laws of Nature are far stronger than those of mankind. Humanity must awake and learn what little time there remains.
We think the topic that we have chosen is actual, because we do not know much about this natural disaster; nevertheless anyone can suffer from it, as a lot of people nowadays travel around the world. According to the fact, cities and towns are usually collapsed and people die. This knowledge can be used in our future, as it helps us to survive.
Hypothesis: People`s actions are not right during and after tsunami.
Object: a tsunami
Subject: our deeds during and after a tsunami.
Goal: to introduce people some useful information and prevent them from making mistakes during such a natural disaster as a tsunami.
In order to achieve our goal we are aiming to:
Find out the reasons of a tsunami formation;
Make a research about this problem;
Make a survey among the students in our grammar school;
Make a brochure of safety rules and signs;
Make a physical experiment.
1.Tsunami
1.1.Definition oftsunami.
The term tsunami comes from the Japanese, meaning "harbor" and "wave". Thetsunami or tidal wave is a series of water waves (called a tsunami wave train) caused by the displacement of a large volume of a body of water, usually an ocean, but can occur in large lakes. Tsunamis are a frequent incident in Japan; approximately 195 events have been recorded. Due to the immense volumes of water and energy involved, tsunamis can devastate coastal regions. Earthquakes, volcanic eruptions and other underwater explosions landslides and other mass movements, meteorite ocean impacts or similar impact events, and other disturbances above or below water all have the potential to generate a tsunami.
Tsunamis are sometimes referred to as tidal waves. In recent years, this term has fallen out of favor, especially in the scientific community, because tsunamis actually have nothing to do with tides. The once-popular term derives from their most common appearance, which is that of an extraordinarily high tidal bore. Tsunami and tides both create waves of water that move inland, but in the case of tsunami the inland movement of water is much greater and lasts for a longer period, giving the impression of an incredibly high inflow. Although the meanings of "tidal" include "resembling" or "having the form or character of" the tides, and the term tsunami is no more accurate because tsunami are not limited to harbors, use of the term tidal wave is discouraged by geologists and oceanographers.
The Greek historian Thucydides was the first to relate tsunami to submarine earthquakes, but understanding of tsunami's nature remained slim until the 20th century and is the subject of ongoing research.
1.2.Generation mechanisms
The principal generation mechanism (or cause) of a tsunami is the displacement of a substantial volume of water or perturbation of the sea. The waves formed in this way are then sustained by gravity. It is important to note that tides do not take any part in the generation of tsunamis.
Tsunamis can be generated when the sea floor suddenly 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, due 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 (see appendix 5).
Tsunamis have a small amplitude (wave height) offshore, and a very long wavelength (often hundreds of kilometers long), which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimetres above the normal sea surface. They grow in height when they reach shallower water. A tsunami can occur in any tidal state and even at low tide can still inundate coastal areas.
1.3.Characteristics
While everyday wind waves have a wavelength (from crest to crest) of about 100 meters and a height of roughly 2 meters, a tsunami in the deep ocean has a wavelength of about 200 kilometers. Such a wave travels at well over 800 kilometers per hour, but due 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. This makes tsunamis difficult to detect over deep water. Ships rarely notice their passage.
As the tsunami approaches the coast and the waters become shallow, wave shoaling compresses the wave and its velocity slows below 80 kilometers per hour. Its wavelength diminishes to less than 20 kilometers and its amplitude grows enormously, producing a distinctly visible wave. Since the wave still has such a long wavelength, the tsunami may take minutes to reach full height. Except for the very largest tsunamis, the approaching wave does not break (like a surf 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 are possible wherever there are large bodies of water, including lakes.
2.Tsunami formation
2.1.Reasons of Tsunami formation
Tsunamis are caused by earthquakes, landslides, falling debris, volcanic explosions, bolides, glaciers, meteorites, nuclear tests.
The main reason of a tsunami formation is tectonic earthquakes. The deadliest natural disaster caused by the tsunami generated from an undersea earthquake on 26 December 2004 in the Indian Ocean has shaken up the world.
Almost all the countries situated around the Bay of Bengal were affected by the tsunami waves in the morning hours.
Aspects that were not immediately brought out by news reports were:
The 9.0 Earthquake at 6.58 hours at the epicenter (and in Sri Lanka) led to a sequence of 15 other quakes across the Andaman region.
While earthquakes could not be predicted in advance, once the earthquake was detected it would have been possible to give about 3 hours of notice of a potential Tsunami. Such a system of warnings is in place across the Pacific Ocean. However, there was no warning system in the Indian Ocean. In addition, coastal dwellers are educated in the Pacific littoral to get to high ground quickly following waves. However, those in the Indian Ocean were quite unaware.
Tsunamis are rarer in the Indian Ocean as the seismic activity is much less than in the Pacific. However, there have been 7 records of Tsunamis set off by Earthquakes near Indonesia, Pakistan and one at Bay of Bengal.
Earthquakes appears when any of the 12 or 13 plate collides at their boundaries. The present heat is due to compression between the Indian and Burmese plates. Scientists now believe that one plate that squeezed the landmass from India to Australia has broken up into two. The initial 8.9 eruption happened near the location of the meeting point of the Australian, Indian and Burmese plates. Scientists have shown that this is a region of compression as the Australian plate is rotating counterclockwise into the Indian plate. This also means that a region of seismic activity has become active in the South Eastern Indian Ocean.
Tsunamis are not entirely unknown in Sri Lanka. For example, the Tsunami in 1883 generated by the Volcanoes at Krakatau led to a surge of at least 1 m in Sri Lanka. The damage was much less then. However, one difference was that this particular episode happened in the month of August. In the month of December, under the North-East monsoon, the Equatorial Indian Ocean jet propagates along the equator from Sumatra (near the epicenter of the quake) slightly to the South of Sri Lanka and to Somalia. This may be why the impact of the quake led to severe impacts in Sri Lanka.
Once the large amount of pent-up energy in the compression zones of the plate boundaries have been released, it takes another buildup of energy for another event of similar magnitude. This is unlikely in the short-term. However, in the future, Indian Ocean littoral regions should generate and pay attention to earthquake and tsunami warnings and be aware of the interplay of the seasonal oceanographic currents.
In the 1950s, it was discovered that larger tsunamis than had previously been believed possible could be caused by giant landslides. These phenomena rapidly displace large water volumes, as energy from falling debris or expansion 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 metres (over 1700 feet). The wave didn't 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. Scientists named these waves megatsunami.
2.2.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 & 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 Mt, calculated from, where h is the maximum tsunami-wave amplitude (in m) measured by a tide gauge at a distance R from the epicenter, a, b & D are constants used to make the Mt scale match as closely as possible with the moment magnitude scale.
Seismic waves are the vibrations from earthquakes that travel through the Earth; they are recorded on instruments called seismographs. Seismographs record a zig-zag trace that shows the varying amplitude of ground oscillations beneath the instrument. Sensitive seismographs, which greatly magnify these ground motions, can detect strong earthquakes from sources anywhere in the world. The time, locations, and magnitude of an earthquake can be determined from the data recorded by seismograph stations.
The Richter magnitude scale was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. Adjustments are included for the variation in the distance between the different seismographs and the epicenter of the earthquakes. On the Richter Scale, magnitude is expressed in whole numbers and decimal fractions. For example, a magnitude 5.3 might be calculated for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; as an estimate of energy, each whole number step in the magnitude scale corresponds to the release of about 31 times more energy than the amount associated with the preceding whole number value.
At first, the Richter Scale could be applied only to the records from instruments of identical manufacture. Now, instruments are carefully calibrated with respect to each other. Thus, magnitude can be computed from the record of any calibrated seismograph.
Earthquakes with magnitude of about 2.0 or less are usually called microearthquakes; they are not commonly felt by people and are generally recorded only on local seismographs. Events with magnitudes of about 4.5 or greater - there are several thousand such shocks annually - are strong enough to be recorded by sensitive seismographs all over the world. Great earthquakes, such as the 1964 Good Friday earthquake in Alaska, have magnitudes of 8.0 or higher. On the average, one earthquake of such size occurs somewhere in the world each year. The Richter Scale has no upper limit. Recently, another scale called the moment magnitude scale has been devised for more precise study of great earthquakes.
The Richter Scale is not used to express damage. An earthquake in a densely populated area which results in many deaths and considerable damage may have the same magnitude as a shock in a remote area that does nothing more than frighten the wildlife. Large-magnitude earthquakes that occur beneath the oceans may not even be felt by humans.
2.3. Warnings and predictions
A Tsunami Warning System (TWS) is a system to detect tsunamis and issue warnings to prevent loss of life and property. It consists of two equally important components: a network of sensors to detect tsunamis and a communications infrastructure to issue timely alarms to permit evacuation of coastal areas.
There are two distinct types of tsunami warning systems: international and regional. Both depend on the fact that, while tsunamis travel at between 500 and 1,000 km/h (around 0.14 and 0.28 km/s) in open water, earthquakes can be detected almost at once as seismic waves travel with a typical speed of 4 km/s (around 14,400 km/h). This gives time for a possible tsunami forecast to be made and warnings to be issued to threatened areas, if warranted. Unfortunately, until a reliable model is able to predict which earthquakes will produce significant tsunamis, this approach will produce many more false alarms than verified warnings. In the correct operational paradigm, the seismic alerts are used to send out the watches and warnings. Then, data from observed sea level height (either shore-based tide gauges or DART buoys) are used to verify the existence of a tsunami.
Other systems have been proposed to augment the warning paradigm. For example, it has been suggested that the duration and frequency content of t-wave energy (which is earthquake energy trapped in the ocean SOFAR channel) is indicative of an earthquake's tsunami potential. The first rudimentary system to alert communities of an approaching tsunami was attempted in Hawaii in the 1920s. More advanced systems were developed in the wake of the April 1, 1946 (caused by the 1946 Aleutian Islands earthquake) and May 23, 1960 (caused by the 1960 Valdivia earthquake) tsunamis which caused massive devastation in Hilo, Hawaii.
In the 2004 Indian Ocean tsunami drawback was not reported on the African coast or any other eastern coasts 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, oceanographers, and seismologists analyze 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 that are attached to buoys. The sensors 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, Hawai. It monitors Pacific Ocean seismic activity. A sufficiently large earthquake magnitude and other information trigger a tsunami warning. While the subduction zones around the Pacific are seismically active, not all earthquakes generate tsunami. Computers help in analysing the tsunami risk of every earthquake that occurs in the Pacific Ocean and the adjoining land masses.
As a direct result of the Indian Ocean tsunami, a re-appraisal of the tsunami threat for all coastal areas is being undertaken by national governments and the United Nations Disaster Mitigation Committee. A tsunami warning system is being installed in the Indian Ocean.
Computer models can predict tsunami arrival, usually within minutes of the arrival time. Bottom pressure sensors relay information in real time. Based on these pressure readings and other seismic information and the seafloor's shape (bathymetry) and coastal topography, the models estimate the amplitude and surge height of the approaching tsunami. All Pacific Rim countries collaborate in the Tsunami Warning System and most regularly practice evacuation and other procedures. In Japan, such preparation is mandatory for government, local authorities, emergency services and the population.
2.4.DART stations
Each DART station consists of a surface buoy and a seafloorbottom pressure recording (BPR) package that detects pressure changes caused by tsunamis. The surface buoy receives transmitted information from the BPR via an acoustic link and then transmits data to a satellite, which retransmits the data to ground stations for immediate dissemination to NOAA's Tsunami Warning Centers, NOAA's National Data Buoy Center, and NOAA's Pacific Marine Environmental Laboratory. The Iridium commercial satellite phone network is used for communication between 31 of the buoys. When on-board software identifies a possible tsunami, the station leaves standard mode and begins transmitting in event mode. In standard mode, the station reports water temperature and pressure (which are converted to sea-surface height) every 15 minutes. At the start of event mode, the buoy reports measurements every 15 seconds for several minutes, followed by 1-minute averages for 4 hours.
The first-generation DART I stations had one-way communication ability, and relied solely on the software's ability to detect a tsunami to trigger event mode and rapid data transmission. In order to avoid false positives, the detection threshold was set relatively high, presenting the possibility that a tsunami with a low amplitude could fail to trigger the station.
The second-generation DART II is equipped for two-way communication, allowing tsunami forecasters to place the station in event mode in anticipation of a tsunami's arrival.
2.5.Fascinating facts
I would like to represent the interesting facts concerning the behavior of animals and people. Not only animals are able to feel the sounds but people too.
Some zoologists hypothesize that some animal species have an ability to sense subsonic Rayleigh waves from an earthquake or a tsunami. If correct, monitoring their behavior could provide advance warning of earthquakes, tsunami etc. However, the evidence is controversial and is not accepted. There are unsubstantiated claims about the Lisbon earthquake that some animals escaped to higher ground, while many other animals in the same areas drowned. The phenomenon was also noted by media sources in Sri Lanka in the 2004 Indian Ocean earthquake. It is possible that certain animals (e.g., elephants) may have heard the sounds of the tsunami as it approached the coast. The elephants' reaction was to move away from the close noise. By contrast, some people went to the shore to investigate and many drowned as a result.
Tsunami can be detected using our human senses. Recognize the tsunami’s natural warning signs.
Feel
Strong local earthquake may cause tsunamis;
Feel the ground shaking severely.
See
As a tsunami approaches shorelines, water may recede from the coast, exposing the ocean floor, reefs and fishes.
Hear
Anomalistic ocean activity, a wall of water and approaching tsunami create a loud «roaring» sounds similar to tat of a train or jet craft.
Run
Don’t wait for official evacuation orders.
Immediately leave low-lying coastal areas.
Move inland to higher ground.
Run if you see a tsunami coming.
3. Practical part
We would like to introduce our methods of the research:
Chart analysis
Graphic model
A brochure
Physic experiment
3.1. Analysis of actions during tsunami
Having interviewed the students, from our grammar school we have come to the conclusion that they don’t know the safety rules during and after a tsunami. That is why, we have analyzed a lot of useful information concerning tsunami signs and the scientists’ articles, that has helped us a lot to make a brochure of safety rules and signs. (see appendix 1, 2, 3, 4).
3.2.Mitigation of Tsunami
Working on our project, we have read a report published by the United Nations Environment Programmer me (UNEP). It suggests that the tsunami of 26th December 2004 caused less damage in the areas where natural barriers were presented, such as mangroves, coral reefs or coastal vegetation. A Japanese study of this tsunami in Sri Lanka used satellite imagery modeling to establish the parameters of coastal resistance as a function of different types of trees. For this reason, we have decided to invent the graphic model. It will show how the beaches should be equipped with natural barriers.
If only the mangroves were intact, the damage from tsunami would have been greatly minimized.
Ecologists have offered the concept that mangroves should provide double protection for the first layer of red mangroves with their flexible branches and tangled roots hanging in the coastal waters absorbing the first shock waves.
The second layer of tall black mangroves operates like a wall withstanding a lot of sea pressure.
3.3.Safety rules at public places
Nowadays, people get a chance to study and work abroad. That’s why it is necessary for them to know how they should behave during the nature disaster: at school, at work, at home.
Be aware of tsunami facts. This knowledge could save your life! Share this knowledge with your relatives and friends. It could save their lives!
If you are in school and you hear a tsunami warning, you should follow the advice of teachers and other school stuff. If you are at home and hear there is a tsunami warning, you should make sure you entire family is aware of the warning. Your family should leave your house if you live in a tsunami evacuation. Move orderly, calmly and safely to the evacuation site or to any safe place outside your evacuation zone.
Follow the advice of local emergency.
If you are at the beach or near the ocean and you feel the earth shake, move immediately to higher ground. Do not wait for a tsunami warning to be announced. Stay away from rivers and streams that lead to the ocean as you would stay away from the beach and ocean if there is a tsunami. A regional tsunami from a local earthquake could strike some areas before a tsunami warning could be announced. Tsunamis generated in distant locations will generally give people enough time to move to higher ground. For locally generated tsunamis, where you might feel the ground shake, you may only have a few minutes to move to higher ground.
High, multi-story, reinforced concrete hotels are located in many low-lying coastal areas. The upper floors of these hotels can provide a safe place to find refuge should there be a tsunami warning and you cannot move quickly inland to higher ground. Local Civil Defence procedures may, however, not allow this type of evacuation in your area. Homes and small buildings located in low lying coastal areas are not designed to withstand tsunami impacts. Do not stay in these structures should there be a tsunami warning.
Offshore reefs and shallow areas may help break the force of tsunami waves, but large and dangerous waves can still be threat to coastal residents in these areas. Staying away for all low-lying coastal areas is the safest advice when there is a tsunami warning.
3.4. Physic experiment
Understanding of how the wave could be destructive, we have decided to do some experiments in order to prove the fact how the wave is powerful.
Firstly, for our experiments, we took:
A retort with some water
Three weights
A measuring ruler
Secondly, we expressed water mass from the law of saving energy:
Thirdly, we did three experiments with matter of different weight and got the results.
Calculations:
The table of results:
|
№ |
m (matter), kg |
h (water), m |
h (height of lifting matter), m |
m (water), kg |
|
I |
0,1 |
0,1 |
0,5 |
0,5 |
|
II |
0,2 |
0,2 |
0,5 |
0,5 |
|
III |
0,3 |
0,3 |
0,5 |
0,5 |
To sum up, we put measuring significance into the formula and got unexpected dependence: in increasing mass matter throwing into the water the height of water mass stays unchangeable.
Then we wanted to explain where the wave’s energy comes from. For this reason, we made the second experiment.
Firstly, for my experiments, we took:
A retort with water
Some sand and rocks for making a coastal line.
A cardboard
Secondly, we measured the height of wave with the help of photo and used the formula of measuring pressure:
Calculation:
In summary, we have proved the idea, that even the small wave can be destructive.
Conclusion
While working on our research work: we have concluded that we are advanced people living in the world full of modern technologies, so we should use all the possibilities which give us a chance to survive.
From our point of view, the Earth has always reminded us to be a human and do not waste the natural resources.
Actually, all our experiments and research work have been made in order to prove the hypothesis of our research work. Undoubtedly, all people from kids to adults should be instructed how to behave in conditions of an imminent disaster. If you know all the safety rules, you have a great chance to escape from disastrous effects.
As a result, we would like to introduce you a booklet containing safety rules and signs. Study it very carefully before going to a coast. It includes all the necessary information about safety behaviour during a tsunami.
Its effectiveness is confirmed by a number of physical experiments, which we have made during the research work. They show that it is possible to reduce the power of the energetic pressure towards the coast line with the help of a system of natural barriers.
Moreover, we have created the graphic model showing a system of natural coast barriers. It provides a double protection against tsunamis. It operates like a wall reducing the power of waves.
The stages of our experiment and all the conclusions we have presented in the tables followed by the graphic model. We have sent it to National Tectonic organisation and believe in its effectiveness.
We stand in silence for a minute to the departed souls in this great calamity world over.
Bibliography:
Dr. Geroge Pararas-Carayannis., Ms Patricia Wilson., Mr. Richard Sillcox. Tsunami warning.
Fradin., Judith Bloom., Dennis Brindell. Witness to Disaster: Tsunamis. Witness to Disaster. Washington, D.C.: National Geographic Society,2008, pp. 42, 43.
Haugen K., Løvholt F., Harbitz C., K; Lovholt., F; Harbitz. Fundamental mechanisms for tsunami generation by submarine mass flows in idealized geometries- 2005.
Marine and Petroleum Geology22: 209–217. Margaritondo G.- 2005. Explaining the physics of tsunamis to undergraduate and non-physics students.Tsunamis. Annual Review of Fluid Mechanics-1987 Vol, S.S.
Thucydides: A History of the Peloponnesian War- 3.89.1–4
Tidal, The American Heritage Stedman's Medical Dictionary. Houghton Mifflin Company- 11 November 2008.
Tsunamis in Greek Literature-17 (2nd ed.). pp. 100–104.
Wikipedia, the free encyclopedia – http://ru.wikipedia.org/wiki/
Appendix 1
Questionnaire form
What is a tsunami?
How does a tsunami happen? Where can a tsunami occur?
How do people protect themselves from a tsunami?
What is it like to live through a tsunami?
How much did you learn?
Interviewing the students in VKontakte and Instagram , we have come to the conclusion that they don’t know the safety rules during tsunami. From our point of view, this problem has risen because our government considers that it is not actual in our country. However, a lot of people travel to the southern coastal regions, where a great probability of tsunami is.
Do you know what tsunami is?
Having analyzed this diagram, we have concluded that 93% of students know the definition of tsunami, and 7% don’t have any ideas about it.
What do you think causes tsunamis?
The second diagram shows that 50% of students think that the movement of a land plato causes the tsunami.
29% do not know anything about tsunami.
14% of them suggest that the strong wind makes the tsunamis.
7% agree that a whirlpool causes the tsunami.
How will you escape from tsunami?
Your actions?
The half of interviewed students supposes that the best way is escaping.
11% of the students choose the safety place on the high places (like mountains, hills)
They think that the best way is evacuate.
The third part has never seen tsunami.
7% want to help their families and the other group of students prefers to find a safety boat.
3% think about staying at home.
Where do tsunamis happen?
24% of the students think that the tsunami happens in Japan.
21% of them guess that they might see the tsunami in China.
Other students think that it happens in Thailand, near the seashore, islands and in the sea.
Appendix 2.
Tsunami Safety Rules
* A strong earthquake felt in a low-lying coastal area is a natural warning of possible, immediate danger. Keep calm and quickly move to higher ground away from the coast.
* All large earthquakes do not cause tsunamis, but many do. If the quake is located near or directly under the ocean, the probability of a tsunami increases. When you hear that an earthquake has occurred in the ocean or coastline regions, prepare for a tsunami emergency.
* Tsunamis can occur at any time, day or night. They can travel up rivers and streams that lead to the ocean.
* A tsunami is not a single wave, but a series of waves. Stay out of danger until an "ALL CLEAR" is issued by a competent authority.
* Approaching tsunamis are sometimes heralded by noticeable rise or fall of coastal waters. This is nature's tsunami warning and should be heeded.
* Approaching large tsunamis are usually accompanied by a loud roar that sounds like a train or aircraft. If a tsunami arrives at night when you can not see the ocean, this is also nature's tsunami warning and should be heeded.
* A small tsunami at one beach can be a giant a few miles away. Do not let modest size of one make you lose respect for all.
* Sooner or later, tsunamis visit every coastline in the Pacific. All tsunamis - like hurricanes - are potentially dangerous even though they may not damage every coastline they strike.
* Never go down to the beach to watch for a tsunami!
WHEN YOU CAN SEE THE WAVE YOU ARE TOO CLOSE TO ESCAPE.
Tsunamis can move faster than a person can run!
* During a tsunami emergency, your local emergency management office, police, fire and other emergency organizations will try to save your life. Give them your fullest cooperation.
* Homes and other buildings located in low-lying coastal areas are not safe. Do NOT stay in such buildings if there is a tsunami warning.
* The upper floors of high, multi-story, reinforced concrete hotels can provide refuge if there is no time to quickly move inland or to higher ground.
* If you are on a boat or ship and there is time, move your vessel to deeper water (at least 100 fathoms). If it is the case that there is concurrent severe weather, it may be safer to leave the boat at the pier and physically move to higher ground.
* Damaging wave activity and unpredictable currents can effect harbor conditions for a period of time after the tsunami's initial impact. Be sure conditions are safe before you return your boat or ship to the harbor.
* Stay tuned to your local radio, marine radio, NOAA Weather Radio, or television stations during a tsunami emergency - bulletins issued through your local emergency management office and National Weather Service offices can save your life.
Appendix 3
Brochure
Appendix 4.
Tsunami photos
(These photos were taken by us after the destructive Tsunami)
( Before the Indian Ocean Tsunami) (After the Indian Ocean Tsunami)
Appendix 5.
Generation mechanisms
Drawing of tectonic plate boundary before earthquake.
Overriding plate bulges under strain, causing tectonic uplift.
Plate slips, causing subsidence and releasing energy into water.
The energy released produces tsunami waves.
Appendix 6.
Tsunami Terminology
Amplitude: The rise above or drop below the ambient water level as read on a tide gage.
Arrival time: Time of arrival, usually of the first wave, of the first wave of the tsunami at a particular location.
Bore: Traveling wave with an abrupt vertical front or wall of water. Under certain conditions, the leading edge of a tsunami wave may form a bore as it approaches and runs onshore. A bore may also be formed when a tsunami wave enters a river channel, and may travel upstream penetrating to a greater distance inland than the general inundation.
CREST: Consolidated Reporting of EarthquakeS and Tsunamis, a project funded through the Tsunami Hazard Mitigation Federal/State Working Group to upgrade regional seismic networks in AK, WA, OR, CA, and HI and provide real-time seismic information from these networks and the USNSN to the tsunami warning centers.
ETA: Estimated Time of Arrival. Computed arrival time of the first tsunami wave at coastal communities after a specific earthquake has occurred.
First motion: Initial motion of the first wave, a rise in the water level is denoted by R, a fall by F.
Free field offshore profile: A profile of the wave measured far enough offshore so that it is unaffected by interference from harbor and shoreline effects.
Harbor resonance: The continued reflection and interference of waves from the edge of a harbor or narrow bay which can cause amplification of the wave heights, and extend the duration of wave activity from a tsunami.
Horizontal inundation distance: The distance that a tsunami wave penetrates onto the shore, measured horizontally from the mean sea level position of the water's edge. Usually measured as the maximum distance for a particular segment of the coast.
ICG/ITSU: The International Coordination Group for the Tsunami Warning System in the Pacific, a United Nations organization under UNESCO responsible for international tsunami cooperation.
IDNDR: International Decade for Natural Disaster Reduction, a United Nations sponsored program for the 1990's.
Inundation: The depth, relative to a stated reference level, to which a particular location is covered by water.
Inundation area: An area that is flooded with water.
ITIC: International Tsunami Information Center established in 1965. Monitors international activities of the Pacific Tsunami Warning Center and assists with many of the activities of ICG/ITSU.
Inundation: The depth, relative to a stated reference level, to which a particular location is covered by water.
Inundation area: An area that is flooded with water.
Inundation line (limit): The inland limit of wetting measured horizontally from the edge of the coast defined by mean sea level.
Leading-depression wave: Initial tsunami wave is a trough, causing a draw down of water level.
Leading-positive wave: Initial tsunami wave is a crest, causing a rise in water level. Also called a leading-elevation wave.
Local/regional tsunami: Source of the tsunami within 1000 km of the area of interest. Local or near-field tsunami has a very short travel time (30 minutes or less), mid-field or regional tsunami waves have travel times on the order of 30 minutes to 2 hours. Note: " Local" tsunami is sometimes used to refer to a tsunami of landslide origin.
Maremoto: Spanish term for tsunami.
Marigram: Tide gage recording showing wave height as a function of time.
Marigraph: The instrument which records wave height.
Mean Lower Low Water (MLLW): The average low tide water elevation often used as a reference to measure runup.
Ms: Surface Wave Magnitude. Magnitude of an earthquake as measured from the amplitude of seismic surface waves. Often referred to by the media as "Richter" magnitude.
Mw: Moment Magnitude. Magnitude based on the size and characteristics of the fault rupture, and determined from long-period seismic waves. It is a better measure of earthquake size than surface wave magnitude, especially for very large earthquakes. Calibrated to agree on average with surface wave magnitudes for earthquakes less than magnitude 7.5.
NOAA: National Oceanic and Atmospheric Administration, the federal agency responsible for tsunami warnings and monitoring. Part of the Department of Commerce.
NWS: National Weather Service, the branch of NOAA which operates the tsunami warning centers and disseminates warnings.
Normal earthquake: An earthquake caused by slip along a sloping fault where the rock above the fault moves downwards relative to the rock below.
Pacific Disaster Center (PDC): An information processing center to support emergency managersin the Pacific region. Funded by the U.S. Department of Defense.
PTWC: Pacific Tsunami Warning Center. Originally established in 1948 as the SSWWS, located in Ewa Beach near Honolulu. Responsible for issuing warnings to Hawaii, to U.S. interests in the Pacific other than the west coast and Alaska, and to countries located throughout the Pacific.
Period: The length of time between two successive peaks or troughs. May vary due to complex interference of waves. Tsunami periods generally range from 5 to 60 minutes.
Runup: Maximum height of the water onshore observed above a reference sea level. Usually measured at the horizontal inundation limit.
Seiche: A standing wave oscillating in a partially or fully enclosed body of water. May be initiated by long period seismic waves, wind and water waves, or a tsunami.
Strike-slip earthquake: An earthquake caused by horizontal slip along a fault.
SSWWS: Seismic Sea Wave Warning System, the original tsunami warning center established in 1948 after the April 1, 1946 tsunami killed 159 in Hawaii.
Teletsunami: Source of the tsunami more than 1000 km away from area of interest. Also called a distant-source or far-field tsunami.
THRUST: The project for Tsunami Hazard Reduction Using System Technology, sponsored by the Office for U.S. Foreign Disaster Assistance/Agency for International Development. A comprehensive program to mitigate tsunami hazards in developing countries.
Thrust earthquake: An earthquake caused by slip along a gently sloping fault where the rock above the fault is pushed upwards relative to the rock below. The most common type of earthquake source of damaging tsunamis.
Tidal wave: Common term for tsunami used in older literature, historical descriptions and popular accounts. Tides, caused by the gravitational attractions of the sun and moon, may increase or decrease the impact of a tsunami, but have nothing to do with their generation or propagation. However, most tsunamis (initially) give the appearance of a fast-rising tide or fast-ebbing as they approach shore and only rarely as a near-vertical wall of water.
TIME: The Center for the Tsunami Inundation Mapping Effort, to assist the Pacific states in developing tsunami inundation maps.
Travel time: Time (usually measured in hours and tenths of hours) that it took the tsunami to travel from the source to a particular location.
Tsunami: A Japanese term derived from the characters "tsu" meaning harbor and "nami" meaning wave. Now generally accepted by the international scientific community to describe a series of travelling waves in water produced by the displacement of the sea floor associated with submarine earthquakes, volcanic eruptions, or landslides.
Tsunami earthquake: A tsunamigenic earthquake which produces a much larger tsunami than expected for its magnitude.
Tsunamigenic earthquake: Any earthquake which produces a measureable tsunami.
Tsunami magnitude: A number which characterizes the strength of a tsunami based on the tsunami wave amplitudes. Several different tsunami magnitude determination methods have been proposed.
TWS: Tsunami Warning System, organization of 26 Pacific Member States which coordinates international monitoring and warning dissemination. Operates through ICG/ITSU
USNSN: United States National Seismic Network, operated by the USGS. Monitors, in real-time, magnitude (M)>5 earthquake activity worldwide and M>3 in conterminous US.UTCUniversal Coordinated Time, international common time system, formerly GMT (Greenwich Mean Time).
UTC: Universal Coordinated Time, international common time system (formerly GMT, Greenwich Mean Time).
WC/ATWC: West Coast/ Alaska Tsunami Warning Center, established in 1967 originally to issue warnings to Alaska of local tsunami events. WC/ATWC is now responsible for issuing warnings for any event likely to impact either Alaska, the west coast of the US, or the Pacific coast of Canada.
WCM: Warning Coordination Meteorologist, regional weather service person responsible for providing information on the tsunami warning system to local agencies.
Appendix 7