What is a natural disaster?

natural disaster - this destructive phenomenon, has enormous power, causing significant damage to the territory in which it occurs.During this type of disaster does more damage.It can be: earthquakes, tsunamis, landslides, droughts, floods, tornadoes, hurricanes and more.

Classification disasters

natural emergencies or natural disasters in Russia and other mills to classify as follows:

1. geological phenomena.
2. Infectious disease in humans.
3. hydrological events.
4. Infectious diseases of livestock.
5. Geophysical hazards.
6. Defeats agricultural plant pests and diseases.
7. Wildfires.
8. Marine hydrological phenomena.
9. meteorological and agro-meteorological phenomena:

• hurricanes;
• storm;
• squalls;
• tornadoes;
• vertical eddies;
• frost;
• tornado;
• showers;
• snowfall;
• drought;
• snowstorm;
• fog and so on. D.

types of disasters and are characterized by the size of the disaster, as well as the number of victims and the extent of the damage, not the area of ​​the destroyed areas.

For example, even the strongest earthquake in the vast unpopulated areas, not related to significant catastrophes, unlike weaker aftershocks that occurred in densely populated regions.

Earthquakes

This is the most terrible natural disasters and the size of the damage, as well as the number of victims.In addition, to protect themselves from such disasters is difficult, since even taking into account what seismologists are making great efforts, earthquakes often occur unexpectedly.

These natural disasters in Russia are more frequent than it seems at first glance.In fact, half of the world's population lives in seismically dangerous regions.

as measured by the earthquake?

Thanks seismographs recorded experts waves and vibrations underground plates.Modern electronic devices can pick up even the faintest tremors, which can not be felt.

In 1935 Charles Richter has created a scale by which made it easy to calculate and compare the capacity of underground vibrations.In fact, the American seismologist perfected the invention of Japanese scientist Wadati.According to the 12-point scale, earthquakes are divided in their power today.

Forecasting and protection

There are three types of forecast: amateur, professional or scientific.There are cases where it is extremely sensitive people do accurate predictions about earthquakes.

same basic methods of forecasting disasters of this type are:

1. Detection of seismically active zones.
2. study of changes in the composition of the gases that come out of the depths.
3. Research slightest change of the speed and duration of the tremors.
4. centers of study of the distribution in space and time.
5. studies of the magnetic field and the electrical conductivity of rocks.

consequences of natural disasters are prevented due to the developed protection measures.They develop competent authorities specializing in the study of seismically dangerous regions in Russia.

What to do during an earthquake?

First of all keep calm as panic can only exacerbate the situation.If you are outdoors, try to stay away from billboards and high-point objects.The greatest risk are the people who run out of the house to find a safe shelter.In fact, it is best to remain in the room, turning off all electrical appliances.It is strictly forbidden to enter the elevator during an earthquake.Such natural disasters begin as abruptly as an end, but nevertheless, after the latest quake is recommended to leave the shelter no earlier than 40 minutes.

tsunami

name "tsunami" comes from the Japanese word that means "big wave washed off the bay."The scientific definition of the disaster is as follows - is the wavelength of a catastrophic nature, arising mainly as a result of the movement of tectonic plates on the ocean floor.

Thus, we can say that it is a natural disaster and cause most earthquake.Tsunami waves can reach a length of 150 to 300 kilometers.In the open sea, such fluctuations are practically invisible.But when the wave reaches shallow shelf, it becomes more and virtually transformed into a huge moving wall.The power of the element can carry entire coastal towns.If a wave hits the shallow bays or estuaries, it becomes even higher.Similarly, as measured by an earthquake, there is a special scale, which allows to characterize the intensity of a tsunami.

• I - tsunami is very weak.The wave is almost invisible, marked only the tide gauge.
• II - Tsunami weak.Can flood flat coast.
• III - Tsunami medium strength.Flat coastal flooding, and may also throw light on the shore of the court.
• IV - A strong tsunami.Fully flooded coast and coastal damage buildings and other structures.Throws to land large sailing ships and small boats.
• V - Very strong tsunami.All coastal areas are flooded and heavily damaged buildings.On shore thrown larger vessels, and causes damage to the internal parts of the coast.With a very strong tsunami are most often victims.This natural disaster is quite common, and from it every year thousands of people suffer.
• VI - The catastrophic tsunami.Coast and coastal area completely emptied.Land and considerable space inland coast completely flooded.It brings a lot of victims.

Forecasting and protection

In the center of Hawaii, Honolulu, is a special service of tsunami warning.In the organization of the data processed by the 31st of seismic stations and tide gauge records of more than 50 posts.In addition, the institution studied these natural disasters and emergencies.Predict the occurrence of a tsunami service can at the earliest 15-20 minutes before the accident.Thus, the message should be sent immediately to have time to take all necessary security measures.

In order to protect against tsunamis, should remain calm, as well as in the case of earthquakes.It should as far as possible away from the coastal strip and try to climb as high as possible.The most dangerous - is that many people prefer to stay on the coast on the roofs of their homes.In fact, the power of the waves can be so devastating that no problems wipe out even the most stable object.Tsunamis - natural disaster, and extremely dangerous.

Volcanic eruptions

Volcanic eruptions are characterized by volcanic processes, which can cause disaster.It may be lava flows, volcanic, hot mud flows, scorching clouds and more.

greatest danger is lava, which is molten rock, heated to a temperature of over 1000 degrees.This fluid flows directly from the cracks in the ground or simply overflowing the crater and flows slowly to the bottom.The consequences of natural disasters caused by the volcanic eruption, are extremely dangerous to humans.

lava flows are also quite a serious threat.Although it seems that the mass moves rather slowly, it should take into account the fact that the heat engenders hot air currents that may threaten human life, even at a great distance.

Forecasting and protection

Experience and practice suggest that lava flows may be resolved with the help of the bombing from aircraft.Due to the velocity of the hot flow slows down considerably.

Today natural disasters like "eruption" liquidated due to artificial troughs that allow take hot flushes.Quite effective method is the construction of protective dikes.

In addition, there is another danger.Mechanical mudslides actually much more dangerous lava and, according to statistics, the number of victims who have suffered from them several times more.The fact that the layers are in the ash rather unstable position.If volcanic ash impregnated with water, it begins to resemble a thin gruel, which can be a huge speed slide from the slope.Protection from mud flows virtually impossible, as they move fairly quickly, and often to evacuate just do not have time.Such disasters in Russia most likely to occur in Kamchatka as in this region has the highest number of active volcanoes.

from weaker mud flows can be prevented by dams or specially designed grooves.In some settlements the inhabitants of Indonesian spread at the foot of the volcano, artificial hills.During a natural phenomenon that is in serious danger, the settlers are climbing these hills and thus avoid hot mud flows.

Another danger is that at a time when glaciers melt from volcanic eruptions, they form a huge amount of water.This may further lead to severe flooding.Thus, and natural disasters can provoke each other.

as dangerous volcanic gases.They contain impurities of sulfur oxide, hydrogen sulfide, and hydrochloric acid.These combinations are deadly to humans.

only protection against such a gas mask.

Landslides

These phenomena are formed when natural processes (or, as often happens, people) violated the stability of the slope.The moment when the power of rock becomes smaller than the force of gravity, the whole earth masses in motion.Sometimes these masses slump on the slopes almost imperceptibly.But in some cases, their speed is relatively high and can be greater than 100 km / h.

largest natural phenomenon of this type is considered to be an event that occurred in 1911 in the Pamir Mountains in Russia.The giant landslide was triggered by an earthquake.According to the researchers, this day slid more than 2.5 cubic kilometers of loose material.It was completely inundated village Usa and all 54 resident.These kinds of catastrophic natural disasters are frequent, not only in Russia but also in many other countries.

If we talk about the number of victims, the worst natural disaster was the landslide that occurred in 1920 in China.In the same way as the Pamirs, the phenomenon was caused by the strong earthquake, which resulted in the loose material has filled the valley Kangxi all of its towns and villages.According to preliminary estimates, killed more than 200,000 people.

Forecasting and protection

only way of real protection from landslides is their warning.Experts - engineers and geologists - have developed a special set of preventive measures intended to prepare the population to such phenomena, and to explain what an accident, disaster, disaster and so on. D.

But unfortunately, when the slump has begun, any of the methods of protectionbecome ineffective.According to studies, the main cause of landslides is water, so the first stage of the enforcement work is to collect and disposal an overabundance of moisture.

predict such natural phenomena is difficult, as in this case, the amount of precipitation does not affect the formation of landslides, as well as the atmosphere.Disasters of this type may occur suddenly and result from earthquakes.

Avalanches

largest avalanches caused the death of more than 10,000 people over the past decade.The fact that the flow rate can range from 25 to 360 km / h.Avalanches are of three types: large, medium and small.Large demolished almost everything in its path with ease razed villages and other objects.Average only dangerous for humans to destroy buildings they can not.Small avalanche and practically not dangerous in principle invisible to humans.

Forecasting and protection

As in other situations, the most important role in the protection of a preventive measure.Experts quite easily determine the avalanche slopes and often disaster relief is not needed.In addition, the majority of avalanches coming down the same routes.

In order to predict the approaching avalanche, is studied in detail the wind direction and rainfall.When snow fell, 25 mm thick, there is a small chance of such a disaster.If the height is 55 mm, the possibility of occurrence of the avalanche increases.And a roll of 100-millimeter fresh snow most likely to avalanche within a few hours.

To protect against disaster avalanche slopes fenced obstruction shields.If the stop element failed attacks made snow slopes.This provoked the gathering of small and less dangerous mass.

floods and natural disaster - flooding

There are two types of flooding: river and sea.To date, these natural phenomena are a threat to ¾ of the world population.

from such natural disasters that occurred in the period from 1947 to 1967, killed more than 200,000 people.For residents of Russia this question is very relevant.For example, the St. Petersburg flood plains 245 times.The largest of these occurred in 1824, and even been described by Alexander Pushkin's poem "The Bronze Horseman".The fact that the city is located at the bottom of the coastal plains, and as soon as the water rises 150 cm, starts oozing moisture.

Forecasting and protection

natural disaster - flooding and its prevention requires respect for the right of land use and development of human settlements.After adjusting the water flow and protecting the surrounding area, you can reduce the threat of flooding to a minimum.Also, it can be sustained barrage dam, which will provide full or partial protection.In order to implement long-term protection of the natural disaster, it is necessary to ensure regular maintenance and control of the coastal zone.

main factor responsible for the intensity of flooding, is the amount of rainfall.It also studied the morphological and biological factors.

Today the World Commission on Emergency Situations have developed special instructions in case of floods and flood.Learn about the most important ones.

1. before the flood is necessary to prepare the sandbags and clean drains, as well as provide a source of energy supply.It is important to stock up on drinking water and food.The elimination of natural disasters of this kind can take quite a long time.
2. During the floods should avoid low-lying places, which ultimately could be flooded.You need to move very carefully.If the water is above the knee, in any case can not move on the flooded areas.Rate power flow visually impossible.
3. After the flood it is not necessary to eat foods that have been stained by flood waters.They may contain bacteria.The same applies to drinking water, which should not be drunk without sanitary inspection.

When forecasting floods, storm surges and flooding are taken into account meteorological factors, as well as the movement of the low pressure areas (cyclones and strong winds).Evaluated morphology of the coast, as well as take into account the state of the water according to the tide tables.

In conclusion

In addition to these natural phenomena, there is also a fire (a natural disaster, or as a consequence of human activity), a tornado, a hurricane and the storm, which are extremely dangerous to human life.