Tsunami(Jap. 津波 IPA: where 津 is “port, bay”, 波 is “wave”). Translated from Japanese, it means "big wave in the harbor" or simply "wave in the harbor." Tsunamis are long waves generated by a powerful impact on the entire water column in the ocean or other body of water.
They have spatial scales from several hundred meters to several hundred kilometers. Tsunami Wave Speed (c) is described by the formula Lagrange:
c=√gh,
where h- depth of the ocean;
g- acceleration of gravity.
Causes of a tsunami.
Tsunamis are not always generated by any one phenomenon, their combination can be the cause. For example, an earthquake and a landslide, a volcanic eruption accompanied by an earthquake and a landslide, and so on.
Most tsunamis are caused by underwater earthquakes(today it is believed that this is the reason that accounts for about 85 % of all tsunamis), during which there is a sharp displacement (raising or lowering) of a section of the seabed. Not every underwater earthquake is accompanied by a tsunami. A tsunami that generates a wave is usually an earthquake with a shallow source. The only problem is the lack of the ability to 100% recognize such earthquakes, because warning services are guided only by magnitude indicators.
Second reason are landslides(near 7% all tsunamis). Having arisen, a landslide immediately generates a wave. An earthquake can cause a landslide. Most often, underwater landslides occur in river deltas.
The third reason are volcanic eruptions(near 5% all tsunamis). Large underwater eruptions have the same effect as earthquakes. A classic example is the tsunami that formed after the Krakatoa eruption in 1883. Huge tsunamis from the Krakatau volcano were observed in harbors around the world and destroyed a total of 5,000 ships and, as a result, about 36,000 people died.
In the age of the use of atomic energy, man has in his hands a means for independently causing concussions, previously available only to nature. Therefore, it should be understood that fourth reason is an human activity. It should be recalled here that in 1946 the United States carried out an underwater nuclear explosion in a 60 m deep sea lagoon with the equivalent of 20,000 tons of TNT. The wave that arose at a distance of 300 m from the explosion rose to a height of 28.6 m, and 6.5 km from the epicenter it still reached 1.8 m. And, although international treaties currently prohibit underwater testing of atomic weapons, but, as practice shows, such agreements are of a formal nature and serve only for the personal reassurance of the citizens of the adjacent territories in their imaginary safety and comfort.
A small, but not so safe percentage of this falls on meteorological reasons(such as the fall of a large celestial body) and other potential causes, described in scientific circles as "unknown" (but very dangerous). Meteorological reasons are a rather little-studied phenomenon today. They are recorded mainly in the Pacific, Atlantic and Indian oceans.
Features of tsunami propagation
Far from the coast, the height of a tsunami is no more than 2-2.5 m, and their length can reach several hundred kilometers. These tsunamis are very gentle and almost imperceptible to ships passing over them.
The speed of tsunamis depends entirely on their depth and can reach speeds of up to 800 km/h. The most interesting thing is that tsunamis are invisible in the open ocean, although they move at a speed of 700-800 km / h, but when approaching the coast, the speed noticeably decreases with a significant increase in the height of the impending wave.
If the tsunami moves towards the coast, then its height, reaching shallow water, begins to increase to 20-30 m, and in some cases it can reach 30-60 m. Near the coast, the tsunami becomes steeper and higher, reaching its peak point along the entire path of its journey.
This leads to huge destruction and numerous human casualties. Examples of such a phenomenon were the coasts of Thailand, Indonesia, India and Sri Lanka during the tsunami on December 26, 2004. in the Indian Ocean, as well as the northeastern part of Japan on March 11, 2011 (the magnitude of the earthquake that generated the tsunami was 9.0 points).
From the point of view of the development of science today, it can be said that the height of a tsunami on the coast and the features of movement inland depend on the size of the initial perturbation of the sea level, the slopes of the bottom, and the configuration of the coastline of the terrain.
Tsunamis are most dangerous in narrowing bays and straits, as well as in the mouth sections of rivers flowing into the sea. Tsunamis travel the farthest along river valleys. Examples of such areas are: the Second Kuril Strait, Tuharka Bay on Paramushir Island, Crabovaya Bay on Shikotan Island, the mouth of the Kamchatka River, and others.
The threat of a tsunami during the day at any point can sharply increase or decrease depending on the fluctuations in the tidal level.
The very first harbingers are animals and birds, which, anticipating danger, leave their habitats in the period from several hours to several days, or even weeks before the impending disaster. As if our Mother Earth herself is taking care to warn the living of danger through various energy waves caught by animals and birds.
For example, residents of earthquake-prone Japan have been determining the danger of tremors by the behavior of aquarium fish for hundreds of years. So, on the eve of the tsunami, Japanese catfish literally try to jump out of the aquarium and constantly rush from wall to wall. Multiple observations, including those conducted by scientists from the Experimental Oceanological Laboratory of the Russian Hydrometeorological University, have also confirmed that oceanic fish also leave coastal waters a few hours before the tsunami. Studies have shown that stingrays, cyprinids, catfish and long-clawed crayfish are especially sensitive to changes in electromagnetic fields before natural disasters.
It is no coincidence that biochemist H. Tributsch notes that, shortly before the onset of earthquakes and the subsequent occurrence of a tsunami, a powerful stream of charged particles or ions rushes from the soil surface into the atmosphere, which saturate the air with electricity to the limit, causing people to have increased excitability, nausea, and headaches. It is these electrostatic fields that force animals to leave dangerous areas. And a group of German researchers from Tübingen, headed by Professor W. Ernst, also found a change in the color of the leaves of flowers, shrubs and trees a few weeks before the earthquakes. Such changes can be recorded using space satellites, which will allow people to be warned of danger in advance.
Signs of a tsunami may also include:
- Sudden rapid withdrawal of water from the shore for a considerable distance and drying of the bottom.
- The occurrence of an earthquake. In tsunami-prone regions, there is a rule that if an earthquake is felt, it is better to move further from the coast and at the same time climb a hill in order to prepare in advance for the arrival of a wave.
- During a storm, only the surface layer of water comes into motion. During a tsunami - the entire water column, from the bottom to the surface.
- A tsunami, as a rule, generates not one, but several waves. The first wave, not necessarily the largest, “wets the surface”, reducing the resistance for subsequent waves.
- The speed of tsunami waves, even near the coast, exceeds the speed of wind waves. The kinetic energy of tsunami waves is also thousands of times greater.
The consequences of the tsunami.
The consequences of the tsunami are huge human casualties. The human life alone is a priceless gift and gift.
According to the first of the seven AllatRa foundations, the highest value in this world is human life. And it is very important to cherish the life of any person as one's own, because although it is fleeting, it gives everyone a chance to increase their main value - their inner spiritual wealth, the only thing that opens the way for the Personality to true spiritual immortality.
The most terrible consequence of a tsunami is the loss of at least one priceless human life.
But, in addition to the death of people, tsunamis also cause flooding of significant coastal areas, salinization and erosion of soils, destruction of buildings and structures, damage to ships moored off the coast. The tsunami deals a huge blow to the economy of the country in which such a disaster occurred. The economic losses from the tsunami are colossal and amount to truly astronomical sums of money allocated to eliminate the consequences and restore the destroyed infrastructure of the region.
An example of this is the event in Japan. According to experts, a year after the earthquake and the resulting tsunami, the damage to Japan is estimated at 210.00 billion US dollars. This tsunami not only became the most expensive natural disaster in history. But it also destroyed 128,582 and partially destroyed 243,914 buildings. Some 320,000 people lost their homes and 15,848 lost their lives. Another 3305 people are considered missing.
What to do in the event of a tsunami?
We must make sure that the documents, the minimum necessary things and products are always at hand.
Arrange with family members for a rendezvous point after a disaster, consider evacuation routes from a dangerous coastal area, or designate places to escape if evacuation is not possible. It can be local hills or high capital buildings. It is necessary to move to them by the shortest route, avoiding low places. A distance of 2-3 km is considered safe. from the shore.
It is important to understand that when observing tsunami harbingers, tremors, or local tsunami warnings, the time to rescue can be measured in minutes. Therefore, it is necessary to act instantly, remaining collected and as calm as possible.
The occurrence of distant tsunamis is recorded by warning systems, and the forecast is reported on radio and television. Such messages are preceded by the sounds of sirens.
It is impossible to predict the number, height of waves, as well as the interval between them. Therefore, after each wave, it is dangerous to approach the shore for 2-3 hours. It is advisable to use the gap between the waves to find the safest place.
Any earthquake felt on the seashore should be considered a tsunami hazard.
You can not approach the coast to look at the tsunami. It is believed that if you see a wave and are in a low place, it is too late to save yourself.
Compliance with these simple rules of conduct, knowledge of tsunami precursors could reduce the number of victims of the tsunami in the Indian Ocean in 2004. Indeed, according to eyewitnesses (this can also be seen on the recorded videos), many people used such a tsunami harbinger as the ebb before the arrival of the wave to walk along the seabed and collect marine animals, shells, as well as various things left after the rapid “leaving” of water during low tide.
With the right behavior, the number of saved people could reach tens of thousands.
It is necessary to pay attention to the development of the sciences in the field of observation of animals, birds, fish and the entire surrounding world, so that, along with these harbingers of the coming changes, be fully armed and informed as much as possible about the impending future.
It is important to understand that in order to reduce the damage from the consequences of the tsunami, it is necessary to treat construction with great responsibility, which should be carried out outside the tsunami impact zone. If this is not possible, build buildings so that they take blows with their short side, and / or place them on strong columns. In this case, the wave will pass freely under the building without damaging it.
If there is a threat of a tsunami, ships moored near the coast must be taken out to sea.
You should also pay attention to your understanding that there are no territories of states on planet Earth.
These are the people themselves, according to their desire and choice, share one indivisible planet, one whole and the only one, splitting it up in all possible ways - for which there is only enough imagination and greed. All this division is just an appearance for the mind and an outlet for the ego, especially the alleged owners of artificially created territories in a distant and not so distant history. We are all Earthlings. We are all inhabitants of the Earth. And it doesn’t matter, in fact, what complexion each of us has, where we live and what we believe.
It is important to support each other, lend a helping hand to your neighbor, take care of the people around you in every possible way. And then no disaster will become an obstacle in the life of every person, but will only be a temporary task, overcoming which by joint forces will be easy and least painful for people “affected” by disasters.
A giant wave never appears just like that, the main thing is to be aware of the dangerous regions and take precautions.
Causes of a tsunami
- Tsunamis are caused by earthquakes, but not every earthquake will necessarily cause a tsunami.
- The great Lisbon earthquake of 1755, which claimed the lives of more than 50 thousand people off the coast of Spain and Portugal, is associated by experts with the tidal effects of the Moon and the Sun on the earth's crust.
- The 1998 tsunami, which demolished everything in its path in the Papua New Guinea region, arose due to a landslide, the descent of which, in turn, provoked an earthquake of medium power ().
- The so-called "meteorological" tsunamis appear against the background of typhoons: after a sharp turn of the typhoon to the side, the resulting wave can continue to move independently (for example, the 2011 tsunami near the English city of Plymouth was caused by a storm in the Bay of Biscay).
- "Exclusive" tsunamis are caused by underwater volcanic eruptions (for example, the tsunami of 1883, formed after the eruption of the Krakatoa volcano), meteorite falls (the documentary of the National Geographic channel mentions traces of a tsunami that remained in Texas after a meteorite fall 65 million years ago ) and man-made disasters.
Philippines, Malay Archipelago
The Philippine Islands are located in a seismically active zone. And where there are earthquakes, there are tsunamis, and it is impossible to predict which of the seven thousand islands will be under attack this year. In 2013, these were the islands of Samar and Leyte, where waves up to 5 meters high claimed the lives of 10 thousand people and left about half a million local residents homeless. And the worst tsunami in the history of the Philippines occurred in 1976, when, as a result of an earthquake in the Cotabato ocean trench, a wave hit the island of Mindanao, killing 8,000 people.
Gizo, Solomon Islands
The Solomon Islands, tiny patches of land scattered across the Pacific Ocean, are defenseless against the destructive power of the tsunami, which was confirmed in 2007, when the cities of Gizo and Noro completely disappeared under water.
Honshu, Japan
In 2012, a 7.9 magnitude earthquake that occurred near the Philippine city of Guan “rolled back” in Japan with a tsunami a little over half a meter high, covering the metropolitan area and Fukushima Prefecture. Compared to the truly horrendous devastation of 2011, when a magnitude 9 earthquake dubbed the "Great East Japan Earthquake" was followed by a tsunami up to 40 meters high, flooding a total area of 561 square kilometers.
Miyagi Prefecture (327 km 2) was hit the hardest, and the highest wave height (40.5 meters) was recorded in Iwate Prefecture. Considering that the word “tsunami” itself came to us from the Japanese language (literally translated as “big wave in the harbor”), the Japanese, who had been familiar with this natural phenomenon for centuries, were not ready for a tragedy of such magnitude.
Maldives
Despite its seemingly vulnerable position, the Maldives archipelago experienced the only major tsunami in 2004. There is a threat, but coral reefs serve as a reliable natural system for protecting the island from surprises from the ocean.
More dangerous than the waves
- The mechanism of formation of a tsunami differs from the mechanism of formation of an ordinary wave, and this is where its danger lies.
- In strong winds, the height of an ordinary wave can significantly exceed the height of an average 5-meter tsunami and even reach a 20-meter mark, but the length of such a wave is no more than a couple of hundred meters.
- During underwater earthquakes, the entire water column comes into motion, so that the length of a tsunami wave is measured in thousands of kilometers, and the speed can reach 1000 km / h.
- An ordinary wave is driven by the wind, and a tsunami carries a huge charge of energy, moving towards land with all its might.
- While the storm wave in narrow spaces loses its pressure, the power of the tsunami, on the contrary, is concentrated there, and it destroys everything in its path.
Phuket, Thailand
A magnitude 9 earthquake brought death and destruction to the Thai island of Phuket in 2004. Despite the fact that the epicenter of the earthquake was in the Indian Ocean near the island of Sumatra, the tsunami that followed it reached the shores of Indonesia, Thailand, Sri Lanka, India and even South Africa. Three waves hit in turn, numerous buildings, local residents and tourists were under water.
Hilo, Hawaii
In the Hawaiian Islands, more precisely, in the city, the International Tsunami Warning Service is located. The place was not chosen by chance: Hawaii is regularly covered by waves about 2 meters high, while the main blow falls on the city of Hilo, which is located on the shores of the bay of the same name. Despite the small wave height, Hawaiian tsunamis are among the most dangerous, because if a person falls into a tsunami wave on one of the local sandy bays with a very short beach, he will simply be smashed against the rocks. But if you are careful, then there is nothing to worry about: all such areas are marked with warning signs, and sirens are installed along the banks of the islands.
Alaska, USA
Alaska had two powerful tsunamis in a row at once: in 1957 and 1958, giant waves covered the Andreanov Islands and Lituya Bay, respectively. In 1958, the impact of the wave was so strong that the whole strip of land was actually destroyed - the La Gaussy spit.
Kamchatka, Russia
Tsunami waves come to Kamchatka from a zone prone to earthquakes, which is located in the Kuril-Kamchatka and Aleutian trenches. The three most powerful attacks of ocean waters occurred in the last century: in 1923, the wave height reached 30 meters, in 1952 - 15 meters, in 1960 - 7 meters.
Iquique, Chile
On May 22, 1960, an earthquake of magnitude 9.5 occurred near the Chilean city of Valdivia, the strongest earthquake in modern human history. And of course, there was a tsunami: in addition to the damage caused directly to the Chilean coast by a 20-meter wave, it reached Alaska, the shores of the Kuril Islands, Japan and swept the Hawaiian city of Hilo, taking about 6 thousand people into the ocean. In 2014, residents of the port town of Iquique were evacuated, where, after an earthquake of 8.2 points, a two-meter tsunami wave came.
Acapulco, Mexico
Despite the fact that the April 2014 earthquake of 7.2 magnitude did not cause a tsunami, the Mexican resorts of Acapulco and Zihuatanejo are under constant threat of a sudden onset of a killer wave. So if the ocean suddenly retreated from the shore, it's time to run.
Tsunami statistics
What to do if "covered"
- If you are in the coastal zone and feel an earthquake, leave the coast within 15-20 minutes.
- If you didn't feel an earthquake, you can guess the approach of a tsunami by a strong ebb tide.
- While the tsunami is approaching, in no case do not waste time in vain: do not go down to look at the exposed seabed, do not shoot the wave with your camera. Immediately look for a hill at least 40 meters in height, preferably warning others about the danger without sowing panic.
- If you are in a building (for example, a hotel) and there is no time left to look for a hill, go up to the upper floors of the building and barricade the windows and doors. Take a safe place: there should be no potentially dangerous objects near you (for example, cabinets that can fall or mirrors that can break).
- If you can't find a hill, try to take cover behind any significant water obstacle (for example, a strong tall tree or a large stone) and cling to it so that you are not carried away by the flow of water into the ocean.
- If a tsunami caught you on the high seas (for example, you were on a ship and you were thrown into the water by a wave), do not panic, take a breath, group yourself and cover your head with your hands. Having surfaced, get rid of wet clothes as quickly as possible and find any object that you can cling to (in 2004 in Thailand, one of the survivors managed to swim out, clinging to the tail of a crocodile, and the other to a python).
- After the elements have raged, do not return to the sea for 2-3 hours: a tsunami is a series of waves.
Photo: thinkstockphotos.com, flickr.com
For many, the danger of a tsunami is a kind of exotic danger. However, the changes in nature in recent years are such that surprises can be expected. Even in a small lake, under certain circumstances, a large wave can occur. Of course, the appearance of large waves is much more likely - a tsunami in the sea and ocean. A very small proportion of the population of Russia lives near the sea, the absolute majority are not threatened by a tsunami. But if you went on vacation to the open sea or ocean...
Where do tsunamis occur most often?
Most earthquakes occur on the Pacific coasts. Accordingly, tsunamis most often occur in the Pacific Ocean. In our country, the Far Eastern shores are exposed to tsunami attacks: Kamchatka, the Kuril and Commander Islands, and partly Sakhalin. Tsunamis also occur in the Indian Ocean. The greatest risk of disaster exists in coastal areas with increased seismic activity. In 2011, a very strong tsunami hit Japan, killing a large number of people, a huge area was washed out and it was the tsunami that provoked the accident at the Fukushima-1 nuclear power plant
Quite often there is a threat of a tsunami in the Philippines, Indonesia, and other Pacific island states.
Going on vacation to such places, it will not be superfluous to have theoretical knowledge of how to behave and what to do during, before and after the tsunami.
Causes of a tsunami
The cause of a tsunami is an underwater earthquake. Powerful shocks create a directed movement of huge masses of water, which roll onto the shore with waves over 10 meters high. Thousands of tons of water with great speed fall on the coast. No residential building can withstand such a load. Houses that are in the way of the waves are washed away completely. There is no chance to survive in the epicenter. The further the wave goes to the ground, the less its strength, but the danger is no less, as the wave turns into a mixture of building materials, stones, fragments of fittings, cars, trees that crush and destroy all life in its path. But the danger doesn't end there either. When the wave passes, these thousands of tons of water, with a huge amount of floating debris, will begin to return to the ocean. Pulling everything you can. People who find themselves in such a stream can be carried out into the open ocean.
Tsunami alert, how to know about a tsunami
The first reason to think about the threat of a tsunami is the announcement of increased seismic activity in coastal areas. If seismologists managed to predict shocks in advance, residents of settlements on the coast should ensure their own safety in case of a tsunami. Such warnings are relevant even if the strength of the earthquake in the city itself is small, because a tsunami occurs when the epicenter of the earthquake is under water.
How can residents and tourists find out about an impending tsunami?
Watch reports and warnings about seismic activity in the region in advance!
To date, in all settlements where there is a possibility of a tsunami, there are special services for alerting the population about the danger. But there is a catch. Earthquakes happen very often, but few reach the tsunami. Therefore, it is not always possible to determine in time. how strong the earthquake will be and whether it will lead to the appearance of a tsunami. And one more thing, if the epicenter of the tsunami is hundreds of kilometers from the coast, then after the notification, the residents will have time to react and evacuate from the dangerous area. But if the epicenter is near the coast, then even if there is an alert, there may not be enough time for evacuation. This is exactly what happened in Japan on the island of Okushiri, during the earthquake off Hokkaido in 1993. Then 230 people died from the tsunami.
At times of increased tsunami threat, one should carefully monitor the messages of the authorities on radio, television via the Internet and SMS informing. In most cases, the danger becomes known in a few hours, which gives residents the opportunity to react. Animals are sensitive to the approach of a giant wave. Long before the onset of a tsunami, they show concern Many wild animals and birds tend to leave the danger area in advance.
The approach of a tsunami in the next 15-20 minutes can be judged by such signs as the rapid retreat of water along the coastline, the sharp attenuation of the surf noise. In some cases, the drift of unusual objects is also observed: fragments of ice or coastal debris raised from the bottom by the current of water. The immediate approach of the wave is accompanied by thunderous sounds, a rumble.
What to do during a tsunami
How to protect yourself and play it safe in case of a tsunami?
In places where there is a high probability of a tsunami, it will not be superfluous to think over your actions in advance. These points should be discussed with the family, agree on a meeting place in case the coast is under threat, and mobile communications turn out to be
inaccessible. In addition, it is important in a calm environment to plan a retreat route taking into account the terrain, avoiding bottlenecks, bays, rivers, places of potential congestion of vehicles and crowds of people. All the most valuable things that will be needed during the evacuation should be at hand and be ready at any time. First of all, documents, a minimum of clothes and a two-day supply of food that do not deteriorate should always be in a specially designated place. You also need a supply of water, a first aid kit, possibly some kind of signaling means (flare gun, hunter's signal), a knife, a rope (paracord), a flashlight, matches in sealed packaging. All this can be folded into a small backpack in case of a quick evacuation.
It is important for residents of coastal areas to take an active part in public events on which protection from the tsunami of the area depends - the construction of dams, shelterbelts, breakwaters.
How to survive a tsunami
In the event that an alarm is announced about the approach of a tsunami, you should urgently leave the coastal area, moving perpendicular to the coastal
lines. Relative safety is provided by an elevation of 30-40 meters above sea level or a distance of 2-3 kilometers from the coast. Such a retreat provides a significant reduction in risk, even if the area is threatened by large tsunamis. But in order to be 100% safe, it is better to move even further or higher.
Retreating from the danger zone, you need to avoid the bed of rivers, streams, ravines. These places are the first to be flooded.
Tsunamis in lakes or reservoirs are less dangerous, but even then caution should be exercised. A safe elevation is considered to be 5 meters above the water level. For this purpose, tall buildings are quite suitable.
With a large tsunami on the sea or ocean, many buildings simply cannot withstand the pressure of the wave of water and collapse. However, if the situation leaves no choice, then high capital buildings are the only chance to survive. They should climb to the highest floors, close windows and doors. how
suggest the rules of behavior during earthquakes, the safest areas in the building are areas near the columns, load-bearing walls, in the corners.
A tsunami is usually a series of several waves and in most cases the first wave is not the strongest. This must be remembered and not to lose vigilance.
If a wave has overtaken a person, it is very important to hold on to a tree, pole, building, and avoid collision with large debris. As soon as the opportunity arises, you need to find a shelter in case of repeated waves.
Photo: a ship washed ashore during a tsunami
How to behave after a tsunami
The main danger of a tsunami is repeated waves, each of which can be stronger than the previous one. It is worth returning back only after the official cancellation of the alarm or not earlier than 2 hours after the cessation of heavy seas at sea. The break between large waves can reach 40-60 minutes.
After returning home after a tsunami, as well as after other natural disasters, you should carefully examine the building for stability, gas leaks, and damage to electrical wiring. Flooding after a tsunami may represent a separate danger.
TEST Option number 1 TSUNAMI
1. Tsunami is...
A) covering the surrounding area with a layer of water; B) displacement of masses of coastal rocks along
slope under the influence of water flows; AT). giant ocean waves that usually occur
as a result of underwater or island earthquakes.
2. What determines the destructive power of a tsunami?
A) from time of day, year and air temperature; B) on the speed of the wave; B) from the direction of movement
waves in relation to the shore; D) from the contour of the coastline, the relief of the coast, the coastal slope.
. 3. What are the known damaging factors of a tsunami?
A) primary, B) tertiary factor C) final factor D) all of the above.
4. What are the secondary consequences of the destructive impact
tsunami?
A) destruction of windows, doors and roofs by an air wave; B) fires resulting from
damage to oil storage facilities, fire hazardous enterprises, sea vessels;
C) destruction of chemically and radiation-hazardous objects; D) all of the above
5. Wave height is:
A) the distance that a tsunami travels in a given time. B) time interval between passes
two successive waves C) the vertical distance between the crest and the bottom of the wave.
6. What to do with early warning of an approach
tsunami?
A) take cover on the roof of the building; B) turn on the TV, radio and listen to the message and recommendations,
strengthen the windows and doors of the lower floors, take documents, stock up on food and water in sealed containers;
C) move valuables to the upper floors, turn off water, electricity; D) take refuge in a safe place
place or head to the collection point. D) all of the above.
7. What causes a tsunami?
A) underwater volcanoes B) underwater earthquakes C) all of the above.
8. What should be done in the event of a sudden arrival of a tsunami, if not
opportunity to leave the building?
A) take cover on the roof of the building; B) take refuge in a building, if possible on the top floor in a safe
place; C) close the doors on constipation. D) all of the above.
9. What is NOT a secondary factor?
A) death of people and animals B) throwing ships on land C) shock wave D) all of the above
10. Signs of an approaching tsunami can be the following phenomena
A) heavy rainfall B) a strong hurricane. C) extreme heat D) animal behavior.
D) temporary retreat of water from the coast.
TEST #2 TSUNAMI 1. The main causes of tsunamis are
A) coastal and underwater earthquakes; B) lightning strikes on a dry tree; B) heavy rains
D) landslides on the seabed.
2. The speed of the tsunami wave in the ocean and on land is:
A) 500 km/h. - 20 km/h B) 1000 km/h - 50 km/h C) 1500 m/h - 150 km/h. D)2000km/h-200km/h
3. The primary damaging factor of a tsunami is ( indicate the correct answer):
A) discharges of static electricity; B) blurring; B) vortex rotating
water flows; D) impact wave
4. What natural phenomenon can cause a tsunami:
A) heavy rainfall B) underwater earthquake; B) an unexpected hurricane;
D) a sharp increase or decrease in air temperature.
5. What is the period of a wave?
A) this is the speed of the tsunami B) the horizontal distance between the tops of the waves. B) time
tsunami passage D) the time interval between the arrival of two successive waves.
___________________________________________________________________________________________
6 How to position the building from the damaging factors of the tsunami:
A) the long side to the tsunami B) the narrow part of the building C) does not matter.
7. The action of the tsunami is not dangerous (specify the correct answer):
A) in the open ocean. B) on coasts with a gentle coast; C) in open bays and bays;
D) on flat coasts;
8 Can the following phenomena be signs of an approaching tsunami?
A) an earthquake B) volcanic eruption; C) a storm of 9 points D) a temporary retreat of water from
coast (low tide); D) an unexpected hurricane;
.9 . When you were notified of the arrival of the tsunami, you made the decision to evacuate, your
next steps (please select correct answer):
A) on the plain, move away from the coast by 2 - 3 km .; b) Climb to an elevated place of safety.
D) all of the above.
______________________________________________________________________________________________
10 Measures to reduce losses from the tsunami (indicate the wrong answer):
A) creation of systems for monitoring, forecasting and warning the population;
B) construction of breakwaters at the entrance to the bay, and coastal dams at the top of the bays;
C) planting trees (pine groves) on dangerous tsunami coasts.
D) straightening the channels of meandering rivers;
TSUNAMI Answers
1. Draw as much air into your chest as possible.
2. Group up and cover your head with your hands.
3. Throw off your clothes and shoes.
4. Get ready for the return movement of the wave.
5. After waiting one wave, use the period of time until the next one to get to a safe place.
6. Take advantage of floating and elevated objects.
WHAT NOT TO DO IN THE EVENT OF A TSUNAMI
· you can not go down to the sea, look at its exposed bottom and watch the waves: when you see a wave, it will be too late to escape from low places;
· you can not meet a wave in a space with a large number of structures or other objects because of the danger of hitting them.
Public actions after did the tsunami come down?
What to do after a tsunami
If you waited out the tsunami in a safe place, then do not rush to return home, wait for the all-clear signal. Return to your original place after making sure that there were no high waves on the sea for two to three hours.
Only after receiving the alarm clear signal can you be sure that there will be no more waves.
When returning, before entering the building, make sure that there is no threat of its collapse due to damage or washing away, make sure that it is strong, check that there are no cracks in the walls and ceilings, that the foundation is not broken, as well as the safety of windows and doors. Wait for the condition of the electrical wiring and gas pipeline to be checked.
Report the state of your home to the emergency commission. Actively join the team to carry out rescue and other urgent work in damaged buildings, search for victims and provide them with the necessary assistance.
TEST Option No. 1 TSUNAMI
A) covering the surrounding area with a layer of water; B) displacement of masses of coastal rocks along
slope under the influence of water flows; AT). giant ocean waves that usually occur
as a result of underwater or island earthquakes.
2. What determines the destructive power of a tsunami?
A) from time of day, year and air temperature; B) on the speed of the wave; B) from the direction of movement
waves in relation to the shore; D) from the contour of the coastline, the relief of the coast, the coastal slope.
. 3. What are the known damaging factors of a tsunami?
A) primary, B) tertiary factor C) final factor D) all of the above.
4. What are the secondary consequences of the destructive impact
A) destruction of windows, doors and roofs by an air wave; B) fires resulting from
damage to oil storage facilities, fire hazardous enterprises, sea vessels;
C) destruction of chemically and radiation-hazardous objects; D) all of the above
5. Wave height is:
A) the distance that a tsunami travels in a given time. B) time interval between passes
two successive waves C) the vertical distance between the crest and the bottom of the wave.
6. What to do with early warning of an approach
A) take cover on the roof of the building; B) turn on the TV, radio and listen to the message and recommendations,
strengthen the windows and doors of the lower floors, take documents, stock up on food and water in sealed containers;
C) move valuables to the upper floors, turn off water, electricity; D) take refuge in a safe place
place or head to the collection point. D) all of the above.
7. What causes a tsunami?
A) underwater volcanoes B) underwater earthquakes C) all of the above.
8. What should be done in the event of a sudden arrival of a tsunami, if not
opportunity to leave the building?
A) take cover on the roof of the building; B) take refuge in a building, if possible on the top floor in a safe
place; C) close the doors on constipation. D) all of the above.
9. What is NOT a secondary factor?
A) death of people and animals B) throwing ships on land C) shock wave D) all of the above
10. Signs of an approaching tsunami can be the following phenomena
A) heavy rainfall B) a strong hurricane. C) extreme heat D) animal behavior.
"It is obvious that the life activity of mankind, as well as other processes in the surrounding world, proceed according to certain laws.
It is also likely that ignoring these laws led to population and natural disasters (wars and natural disasters)."
The spontaneous actions of the forces of nature, which are not yet fully subject to man, cause enormous damage to the economy of the state and the population.
The most important dangerous trend in the development of natural disasters is the reduction in the protection of people and the technosphere. The number of deaths on Earth from natural disasters over the past 35 years has increased annually by an average of 4.3% and amounted to 3.8 million people, and the number of victims increased annually by 8.6% and reached 4.4 billion people over the same period of time.
The problems with the climate and our ability to adapt to its changes are also evidenced by the statistics of natural disasters in 2006. The sad results of last year, with the support of the UN, were presented at a press conference in Geneva by the Belgian Center for the Study of the Epidemiology of Natural Disasters.
From the report of the Center it follows that more than 21 thousand people have become victims of almost 400 natural disasters around the world. Almost 75% of all human losses occur in Asian countries. The biggest disaster of the year was the May earthquake in Indonesia. It killed 5800 people. But in second place in terms of the number of victims was Europe. In July last year, an unprecedented heat wave claimed almost 2,000 lives in Holland and Belgium, and before that, in January, 940 residents of Ukraine became victims of a sharp cold snap.
In addition, this year there will be more typhoons, earthquakes, forest fires, floods, or at best, their number will remain at the level of 2006. This conclusion follows from the traditional annual report of the Ministry of Emergency Situations of the Russian Federation on the cataclysms that await Russia in 2007.
Natural and human factors will traditionally be responsible for the revelry of the elements. Moreover, the latter will lead to an increase not only in man-made disasters, but will also affect natural factors. In particular, this year, global warming has been recognized as one of the new potential sources of danger for the first time.
The forecast of troubles begins with global factors - such as an increase in the overall temperature on the planet and changes in solar activity during the year. The forecast of rescuers notes that the average annual air temperature on the planet has increased by 0.6 degrees in the last century. The rate of thawing of permafrost in this case can reach unprecedented values - 20 centimeters per year. The increase in global climate temperature, according to analysts of the Ministry of Emergency Situations, carries a number of threats.
First, the melting of ice, in particular, can cause massive deformation and destruction of buildings. However, this phenomenon is far from universal, it is typical only for permafrost regions.
Secondly, an increase in the frequency of collisions of cold and warm air masses with a high level of temperature contrast leads to an increase in the number of hurricanes, heavy precipitation, floods and floods. The main part of typhoons, as usual, will fall on the Far East, primarily on the Kuril Islands. Their number is predicted at the level of 26-28, in five cases the parameters of typhoons, according to the Ministry of Emergency Situations, will pose a threat to the emergence and development of emergencies at the territorial and federal levels.
Thirdly, intensive melting and retreat of glaciers increases the risk of large-scale landslides and mudflows. Over the past 50 years, according to the Ministry of Emergency Situations, the glaciers of the Caucasus have retreated by more than 300 meters on average. This formed the conditions for natural disasters of rare frequency (in the Krasnodar, Stavropol Territories, Kabardino-Balkaria, Karachay-Cherkessia, North Ossetia and Dagestan).
Also, warming can affect the increase in the number and scale of natural emergencies, primarily forest fires.
The subject that has a destabilizing effect on the environment is humanity. Mankind, equipping itself, “reshapes” the surface of the Earth-object (intensively builds and expands cities, destroys forests, constructs drainage and irrigation canals, artificial seas, dams, drains swamps), dumps into the atmosphere a huge mass of garbage, dust and gases, concentrates energy-intensive facilities, i.e. introduces a powerful imbalance into the environment.
In this case, the reaction of the environment is inevitable and, as the facts show, unpredictable. For humanity, the reaction of the environment turns into a natural disaster.
The destructive force, magnitude, frequency of repetition of the reaction of the environment (natural disasters) will gradually increase. What we have seen in the last decade. More and more territories of North America, Europe, Asia, Australia are covered by natural disasters: powerful hurricane winds, tsunamis, excessive precipitation, floods, drought, forest fires, etc., p.r. Moreover, such natural anomalies until recently appeared once or twice in a hundred or two hundred years, once a decade. In the last decade, in some parts of the world, natural anomalies have been manifesting themselves annually, or even twice a year.
In fact, soon humanity will face the question of survival. Entire countries can be wiped off the face of the earth. It is urgent to develop a new concept of the relationship of mankind with the environment. The concept should include evidence-based recommendations:
Equipping itself, humanity must predict the prerequisites for a destabilizing impact on the environment. If the prerequisites arise, it is necessary to stop the development or provide for the processes of compensation, absorption or neutralization of destabilizing factors.
The scientific thought of mankind should be directed as much as possible to the development of methods for determining the zones of the formation of the reaction of the environment (the zones of the formation of tornadoes, hurricanes, tsunamis and others) to find ways to neutralize, absorb, compensate and weaken the reaction of the environment.
Of course, it is hardly possible to prevent floods, earthquakes, tornadoes, typhoons, droughts, and other natural disasters in the future. But we can reduce the threat of the elements. First of all, relying on scientific data, studying the information received from meteorologists, various emergency response services, to predict, predict this or that natural phenomenon characteristic of a region or city. This makes it possible to reduce the risk of natural disasters, the damage from them. Another thing is also important: it is necessary to take all measures to reduce the risk of natural disasters, to teach the population how to prevent emergencies, how to behave in the face of dangerous natural phenomena.
List of used literature
Arustamov E.A. Life safety. – M.: Phoenix, 2006.
Belov S.V., Devisilov V.A., Ilnitskaya A.V., Kozyakov A.F. Life safety. - M .: Higher school, 2007.
Krummenerl Reiner. Natural disasters. - M .: World of Books, 2007.
Nepomniachtchi N.N. Natural disasters. – M.: AST, 2006.
Great natural disasters: floods, earthquakes, volcanoes, tornadoes. Oleinik T.F. – M.: Phoenix, 2006.
Osipov V.I. The global impact of natural disasters on the fate of peoples. – M.: Phoenix, 2000.
Petrov S.V. BZD: State educational standards. – M.: Infra, 2005.
Rezchikov E.A. Tkachenko Yu.L. Fundamentals of life safety. – M.: Equilibrium, 2003.
Rezchikov E.A. Life Safety: Textbook. – M.: MGIU, 2006.
Temkin A.N. Natural disasters and their patterns to study in order to prevent. – M.: Phoenix, 2007.
Fundamentals of life safety. Proc. Benefit. - Voronezh: NPO "MODEK" Publishing House, 2005.
Journal "Fundamentals of life safety" №2, 2007
A tsunami is a natural disaster that anyone can experience. Even if you do not live in a tsunami-prone area, you may find yourself in one on vacation or on a business trip. Therefore, any person should know how to behave when such a phenomenon occurs.
It must be understood that a tsunami is not just a big wave, but a much more powerful force, which is described by a separate physical formula and has a force almost equal to that of an explosion. In the sea, a tsunami is practically invisible - the wave acquires its height and power when it approaches shallow water.
What not to do during a tsunami
To begin with, we will tell you what not to do during a tsunami so that you do not make serious mistakes.
Firstly, you can’t stand spellbound and look at a huge wave, as if rooted to the spot. Perhaps this recommendation will seem strange to you: who would ever think to stand and watch? But, as practice shows, many do just that. Either out of fear or out of curiosity.
Secondly, if the tsunami is already very close, just running will not help, because the wave moves at a speed of 800 km per hour (aircraft speed), but the closer to the coast, the slower it becomes: the speed decreases to 80 km per hour.
Thirdly, if the tsunami is still far away, but it is already known, most likely you have no more than 15-20 minutes to escape. Therefore, instead of collecting our things, we use the time to escape. We take only the essentials. Save not things, but life!
Fourthly, you should not run near the riverbeds: it is the riverbeds that will spill in the first place during a tsunami.
When the tsunami hit the shores of Thailand in 2004, vacationers were surprised that the bottom was exposed for many kilometers and various shells became visible, which people began to collect. But on one beach, vacationers were saved by the knowledge of a schoolgirl, who on the eve of a geography lesson went through the topic of a tsunami and recognized the exposure of the seabed in time as a sure sign of the onset of a wave, and also informed everyone around about it, so that they managed to evacuate.
Signs of a tsunami include:
- earthquake
- unusual behavior of water: it either retreats many meters, or, conversely, begins to “lubricate” the surface of the earth, as it were, going beyond the water area
- animals have run away from the shore or are behaving anxiously
- the appearance of a white edge of a wave on the horizon
- sharp rise in the sea horizon
- all people run from the sea
- the warning siren wails
What to do during a tsunami
If you don't see the tsunami yet, but the warning siren is already sounding, or if you only saw the tsunami on the horizon, then you have 10 to 20 minutes to leave the place.
Immediately start running to the other side of the sea. Don't stop until you're 3-4 kilometers inland or 30 meters up. Usually this is enough to save.
If you are trapped and cannot leave the shore, climb up. This is not the best solution, so we use it only if all other solutions are not available. You can climb onto the roof of the building, or you can choose a strong tall tree for shelter.
When you take a position from where you will wait for the onset of the wave or start to run, try to get rid of heavy pieces of clothing on the go(jackets, etc.), which, if the wave overtakes you, will sink you.
If you fall into the water, climb onto the floating object and use it as a raft. Whenever possible, try to climb a tree, a building, or some other safe place.
Once in a tsunami, you have a chance to die not from drowning, but from the impact of some floating object. So try to protect yourself from such items.
When the wave reaches its limit on land, it will begin to retreat with great force. Being in the water at this time is extremely dangerous, because you will simply be carried into the ocean. Therefore, whenever possible, try to get out of the water, even if just clinging to a tree, to overcome the force that carries you into the ocean.
What to do after a tsunami
When the tsunami has receded, you can not return to your house or hotel, go to the shore. The first wave may be followed by the second and third, and they may be stronger. Therefore, you need to stay far from the coast, or even better, try to go deeper into the island or mainland so that the second and third stronger waves do not overtake you. Only when the authorities give a signal that the waves are over, you can return to the house.
When you enter the house, if something is left of it, you need to beware of objects that can fall on your head. You may also be electrocuted. Therefore, you can enter the room only after making sure that everything is in order.
If you're just going on vacation
Of course, it is not very pleasant to think about the bad before going on vacation. But still, forewarned is forearmed. So first find out if tsunamis have hit this coastal region before. Although even if they did not collapse, this is not a guarantee. It is worth considering that most tsunamis occur in a place called the "volcanic belt". This is an area in the Pacific Ocean known for its volcanic activity. However, tsunamis occur in all oceans, so if you are on the ocean coast, it is potentially dangerous. You should not refuse such a vacation, you just need to study the signs of a tsunami and strictly follow all the rules.
Back to the list of articles
Tsunami Warning System
The Pacific Tsunami Warning System (TWS) includes 25 states, including Russia, whose coastal areas are affected by tsunamis.
Remote earthquake warning
When a strong earthquake occurs in the Pacific Ocean, the Pacific Center informs all members of the SPC of the time, coordinates and strength of the earthquake. The first information about a tsunami comes from sea level observation stations located in close proximity to the epicenter of the earthquake. If confirmation of the formation of waves is received, then in case of the approach of a destructive tsunami and to bring the operational services of the TCPC to a state of readiness, it transmits a warning.
- Signs of a tsunami threat:
- a strong earthquake with a magnitude of 6 points or more - when the vibrations of the earth's surface make it difficult to walk, buildings stagger, pendant lamps sway strongly, dishes fall and beat, objects fall from shelves, furniture can move. Strong fluctuations last 20 seconds or more;
- a sudden rapid departure of water from the coast for a considerable distance and drying of the bottom, while the noise of the surf stops (do not try to go down to the water to check this!). The further the sea recedes, the higher the tsunami waves can be;
- a rapid drop in sea level at high tide or a rise at low tide;
- unusual drift of ice and other floating objects, formation of cracks in the fast ice;
- huge reverse faults at the edges of immovable ice and reefs, the formation of crowds, currents.
What to do in case of a tsunami threat
- If you are outside the warning zone or in hard-to-reach coastal areas, then when signs of a threat are detected, you should remember that tsunami waves can reach the coast 15-20 minutes after the earthquake starts. During this time, you must immediately take protective measures:
- it is necessary to leave the coast inland to a hill where the height above sea level is 30-40 meters. If you are on the shore of a closed bay, then this height should be at least 5 meters; it is necessary to leave the coast up the slopes, and not along the river valleys, since the tsunami penetrates the farthest inland along the rivers;
- in the absence of a hill nearby, it is necessary to move away from the coast by at least 2-3 kilometers.
Firemen's website | Fire safety
Latest publications:
Natural disasters, due to their suddenness, are among the most dangerous and destructive emergencies. Often, due to the too rapid development of the disaster, it is not possible to notify the population in advance, or there is very little time left for a complete evacuation. In such cases, a person can survive only thanks to his knowledge. Let's consider what correct actions of the population during a tsunami can increase the chances of survival, and how to get a minimum of injuries and injuries.
The occurrence of giant waves that arise and fall on land with a short period of time is called a tsunami. The main feature of such waves is that they arise from the very bottom and rise up to the surface of the water. The waves of the Pacific Ocean develop the highest speed.
On land, they go most often at a distance of 2 to 4 km inland. From the height and speed of the collapse of water, under the influence of its force, the coastline is washed out and buildings collapse, you can read the actions during the collapse in another article. As a result of the tsunami, fires, power outages, environmental and chemical pollution, and many human casualties occur. Recovery and return to the old life takes a long time.
How to spot a tsunami
Why such huge waves appear, what are their causes and whether it is possible to somehow prevent their development - we will consider further.
In most cases, the basis is natural phenomena that occurred not very far from the coastline:
- underwater earthquakes of at least 7 points
- landslides, depending on the slope of the mainland
- falling into the water column at high speed of huge objects: ice blocks, rocks, meteorite.
- Large volcanic explosions produced by volcanic eruptions
- Human activity, which is carried out at great depths, not far from the bottom.
Warning and actions of the population during a tsunami
Sometimes the possible occurrence or approach of giant waves of water is warned using all the media, as well as by turning on warning sirens. From the moment of notification to the collapse of a tsunami, it can take several minutes or several hours.
Having heard the civil defense signal “Attention to all” in the form of a siren, you should quickly turn on the TV or tune the radio to any radio wave to listen to verbal information. Typically, beeps are heard within 3 minutes. Only after that, the transfer of important information about the algorithm of action during the tsunami begins, as well as the approximate time of its arrival and how the evacuation will be carried out.
Messages are repeated several times. After listening to it, start acting immediately, as time is very short.
- The chance to survive the tsunami is only on a hill. When leaving home, take only the essentials: documents, warm and dry clothes, clean drinking water. All this should be compactly packed in a waterproof bag or airtight bags. Also, do not forget to turn off the electricity in the apartment in a panic and turn off the gas (if any).
- The optimal height above ocean level for safe waiting out of a disaster is 30-40 m. When getting to the shelter, do not go along the mouths of the rivers, it will be safer to choose the path through the hills and slopes.
- If there is no natural hill nearby, then you should move away from the coastline. A more or less safe distance will be 3-4 km.
- In cases of being indoors and not having enough time to go to the most suitable and safe place: you need to go up to the upper floors, find a place without windows, glass and other dangerous objects.
- Never leave solid buildings. In open space, you are much less likely to survive.
- While outside, try to find a reliable tree and take the highest place on it. As protection, you can use concrete structures that you can grab on to.
- You should know that the first wave is not the strongest. It only moistens the earth for subsequent water collapses. In this case, even if you survived the first collapse safely, you cannot leave the shelter, come close to water, or return to your home. It is better to spend this respite in order to protect yourself and find a safer place.
- If you understand that you do not have time to hide, then take more air into your lungs, and once inside the wave, try to group yourself, protecting your head with your hands. Remember that fragments of furniture, houses, glass, cars that rush at a good speed and chaotically pose a great danger in water. Try to press your head to your neck, do not lift it.
- When you surface, look around. Perhaps you will see something in the water that will help you get hooked and stay afloat. It is best to pay attention to tall objects that rise above the water (roofs, pillars, trees).
It is possible to leave the shelter and/or a safe place only after notification of the Ministry of Emergency Situations. Usually, after the first wave, several hours must pass before the tsunami completely collapses on land. When you return to your home, be careful. Check it for damage.
If the load-bearing walls are destroyed or damaged, then it is dangerous to go inside. Look carefully under your feet. Often during a tsunami breaks electrical wires. Do not use an open flame as there may be a gas leak.
