What is spontaneous disaster? Natural disasters and their classification

The spontaneous disaster is a destructive phenomenon, possessing enormous power, causing significant damage to the territory on which it occurs. In the process of a disaster of this type, much damage is done. These can be: earthquakes, tsunamis, landslides, droughts, floods, tornadoes, hurricanes and much more.

Classification of natural disasters

Emergencies of a natural nature, or natural disasters, in Russia and other countries are classified as follows:

1. Geological phenomena.
2. Infectious diseases of people.
3. Hydrological phenomena.
4. Infectious diseases of cattle.
5. Geophysical hazards.
6. Defeat of agricultural plants by pests and diseases.
7. Natural fires.
8. Marine hydrological phenomena.
9. Meteorological and agrometeorological phenomena:

• Hurricanes;
• Storms;
• Squalls;
• Tornadoes;
• Vertical vortices;
• Frost;
• tornado;
• Showers;
• Snowfalls;
• drought;
• Snowstorms;
• Fogs, etc.

Types of natural disasters are characterized by the magnitude of the disaster, as well as the number of victims and the amount of damage inflicted, and not the area of the destroyed territory.

For example, even the most severe earthquakes that occurred in a vast uninhabited area are not significant catastrophes, unlike the weaker shocks that occurred in densely populated regions.

Earthquakes

These are the most formidable and natural disasters in terms of the damage caused, as well as the number of victims. Moreover, it is rather difficult to protect oneself from such catastrophes, since even when considering that seismologists make great efforts, earthquakes most often occur unexpectedly.

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

How are earthquakes measured?

Thanks to seismographs, specialists register waves and vibrations of underground plates. Modern electronic devices allow you to catch even the weakest tremors, which can not be felt.

In 1935 Charles Richter created a scale, thanks to which it was possible to easily calculate and compare the power of underground vibrations. In fact, the American seismologist improved the invention of the Japanese scientist Vadati. According to this 12-point scale, earthquakes are divided by their capacity today.

Forecasting and protection

There are three types of forecast: amateur, professional or scientific. There were occasions when it was sensitive people who made extremely accurate predictions of earthquakes.

The main methods of forecasting catastrophes of this type are:

1. Identification of seismically active zones.
2. The study of changes in the composition of gases that come from the depths.
3. Investigation of the slightest changes in the ratio of the speed and duration of the tremors.
4. Study of the distribution of foci in space and time.
5. Studies of the magnetic field, as well as the electrical conductivity of rocks.

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

What to do during an earthquake?

First of all, one should remain calm, because panic can only exacerbate the situation. If you are on the street, try to stay away from billboards and high point objects. The greatest danger is faced by people who run out of houses in search of more reliable shelters. In fact, it's best to stay indoors, turning off all electrical appliances. It is strictly forbidden to enter the elevator during an earthquake. Such natural disasters begin as unexpectedly as they end, but nevertheless, after the last tremor, it is recommended to leave the shelter no sooner than in 40 minutes.

Tsunami

The name "tsunami" comes from the Japanese word, which stands for "the big wave that washes away the bay". The scientific definition of this natural disaster is as follows: long waves of a catastrophic nature, arising mainly from the movement of tectonic plates on the ocean floor.

Thus, we can say that this disaster is spontaneous and is caused most often by an earthquake. Tsunami waves can reach a length of 150 to 300 kilometers. In the open sea, such fluctuations are almost invisible. But when the wave reaches the shallow shelf, it becomes higher and practically turns into a huge moving wall. The power of the elements can carry whole coastal cities. If the wave enters the shallow bays or at the mouth of the rivers, it becomes even higher. Just as an earthquake is measured, there is a special scale that allows you to characterize the intensity of a tsunami.

• I - Tsunami is very weak. The wave is almost imperceptible, it is noted only by tide gauges.
• II - Tsunami is weak. Can flood flat coasts.
• III - Tsunami of medium strength. It floods flat coasts, and can also throw light ships ashore.
• IV - Strong tsunami. Completely floods the coast and damages coastal structures and other structures. He throws large sailing vessels and small motor boats onto land.
• V - Very strong tsunami. All seaside territories are flooded, and structures are badly damaged. On the shore, larger ships are thrown out, and damage is also inflicted on the inland parts of the coast. With a very strong tsunami, there are often human casualties. Such a spontaneous disaster is quite common, and thousands of people suffer from it every year.
• VI - Catastrophic tsunami. The coast and the seaside territories are completely devastated. The land and considerable space deep into the coast are completely flooded. Brings dozens of victims.

Forecasting and protection

In the center of the Hawaiian Islands, in Honolulu, there is a special tsunami warning service. The organization processes the data of the 31st seismic station, as well as records of more than 50 gauging stations. Among other things, the institution is studying similar natural disasters and emergencies. Predict the appearance of the tsunami service can be the earliest 15-20 minutes before the accident. Thus, the message must be transmitted immediately in time to take all necessary security measures.

In order to protect yourself from the tsunami, you should remain calm, as well as in the case of earthquakes. It is necessary as far as possible to move away from the coastal strip and try to climb as high as possible. The most dangerous thing is that many people prefer to stay on the coast on the roofs of their homes. In fact, the strength of the wave can be so devastating that without problems, even the most stable object will be erased from the face of the earth. Tsunami - the disaster is spontaneous and extremely dangerous.

Volcanic eruptions

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

The greatest danger is lava, which is a melt of rocks heated to a temperature of more than 1000 degrees. This fluid flows directly out of the cracks in the ground or simply overflows the edge of the crater and slowly flows to the foot. The consequences of natural disasters caused by the volcanic eruption are extremely dangerous for humans.

Lava flows are also a rather serious threat. Despite the fact that it seems that the mass is moving rather slowly, it is worth considering the fact that a high temperature generates hot air currents that can threaten human life even at a great distance.

Forecasting and protection

Experience and practice suggest that lava flows can be eliminated by bombing from aircraft. Due to this, the speed of movement of hot streams slows down considerably.

To date, natural disasters such as "eruptions" are eliminated through artificial gutters, which allow you to remove hot currents. A rather effective method is the erection of safety dams.

In addition, there is another danger. Mechanical mud flows are actually much more dangerous than lava and, according to statistics, the number of victims affected by them is many times greater. The fact is that the layers of ash are in a rather unstable position. In the event that volcanic ash is saturated with water, it begins to resemble liquid porridge, which can roll down from a slope with enormous speed. It is almost impossible to protect themselves from these mud flows, as they move rather quickly, and more often than not there is no time for evacuation. Such natural disasters in Russia most often occur in Kamchatka, since it is in this region that the largest number of active volcanoes are located.

From weaker mud flows can be protected by dams or specially designed gutters. In some Indonesian settlements, residents are laying artificial hills at the foot of the volcano. During a natural phenomenon that threatens serious danger, settlers climb these hillocks and thus avoid hot mud flows.

Another danger is that at a time when glaciers are melting from volcanic eruptions, they form a huge amount of water. This in the future can lead to severe flooding. Thus, catastrophes and natural disasters can provoke each other.

Volcanic gases are also dangerous. They contain impurities of sulfur dioxide, hydrogen sulphide and hydrochloric acid. These combinations are deadly to humans.

The only protection against such gases is a gas mask.

Landslides

These phenomena are formed in the case when the stability of the slope is disturbed by natural processes (or, as is usually the case, by humans). At the moment when the strength of the rocks becomes less than the force of gravity, the entire earth mass comes into motion. Sometimes such masses slip on the slopes almost imperceptibly. But in some cases, the speed of their movement is quite high and can be more than 100 km / h.

The largest natural phenomenon of this type is the event that occurred in 1911 in the Pamirs in Russia. The giant landslide was triggered by an earthquake. According to researchers, on this day more than 2.5 cubic kilometers of loose material slid. The village of Usoy and all 54 residents were completely flooded. Such catastrophic types of natural disasters occur quite often not only in the territory of Russia, but also in many other countries.

If we talk about the number of victims, then the most terrible landslide was a natural catastrophe, which occurred in 1920 in China. Just like in the Pamirs, the phenomenon was caused by a strong earthquake, as a result of which loose material flooded the Kansu valley, all its cities and villages. According to preliminary estimates, more than 200,000 people died.

Forecasting and protection

The only way to really protect against landslides is to warn them. Specialists - engineers and geologists - have developed a special set of preventive measures designed to prepare the population for such phenomena, as well as to explain what is an accident, disaster, natural disaster, etc.

But unfortunately, when the slump has already begun, any methods of protection become ineffective. According to studies, the main cause of landslides is water, so the first stage of protection works is the collection and removal of excess moisture.

It is rather difficult to predict such natural phenomena, since in this case the amount of precipitation does not affect the formation of landslides, as well as the atmosphere. Natural disasters of this type can occur unexpectedly and become a consequence of earthquakes.

Snow avalanches

The largest avalanches have caused more than 10,000 deaths in the last decade. The fact is that the flow velocity can vary from 25 to 360 km / h. Avalanches are of three types: large, medium and small. Large demolish almost everything on their way, they easily erase villages and other objects from the face of the earth. Medium are dangerous only for people, as they can not destroy buildings. Small avalanches are practically not dangerous and in principle invisible to humans.

Forecasting and protection

As in other situations, the most important role in the defense is played by preventive measures. Specialists easily identify avalanche slopes and, most often, the elimination of the consequences of natural disasters is not needed. In addition, most avalanches descend along the same routes.

In order to predict the approach of the avalanche, the direction of the wind and the amount of precipitation are studied in detail. If the snow fell 25 mm thick, then there is a small probability of such an element. If the height is 55 mm, then the possibility of an avalanche increases. And with the fall of 100-mm fresh snow, there is the greatest probability of an avalanche in a few hours.

To protect against natural disasters avalanche dangerous slopes are protected by barrier shields. If the elements could not be stopped, the snow slopes are fired. This provokes the gathering of small and less dangerous masses.

Floods and natural disasters - flooding

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

From such natural disasters, which occurred in the period from 1947 to 1967, more than 200 000 people died. For residents of Russia this issue is very relevant. For example, St. Petersburg was flooded 245 times. The largest of them occurred in 1824, and was even described by Alexander Pushkin in the poem The Bronze Horseman. The fact is that the city is located in the lower part of the coastal plain, and as soon as the water rises by 150 cm, the seepage of moisture begins.

Forecasting and protection

Natural disaster - flood and its prevention requires compliance with the rules of land use and proper development of settlements. By adjusting the flow of rivers and protecting adjacent areas, you can reduce the threat of floods to a minimum. Also, it can be resistant dams that will provide full or partial protection. In order to carry out long-term protection against a natural disaster, it is necessary to provide regular care and monitoring of coastal zones.

The main factor responsible for the intensity of floods is the amount of precipitation. For this, morphological and biological factors are also investigated.

To date, the World Commission on Emergencies has developed special instructions for floods and floods. Let's get acquainted with the most important of them.

1. Before the flood, it is necessary to prepare sandbags and to clean the sewerage, and also provide themselves with power supplies. It is important to stock up on drinking water and food. Elimination of natural disasters of such a plan can take quite a long time.
2. During a flood, low-lying areas should be avoided, which, in the final analysis, may be flooded. It is necessary to move extremely cautiously. If the water is above the knees, in no case can the flooded areas pass. It is not possible to evaluate the strength of the flow visually.
3. After a flood, you should not eat foods that have been damped by flood waters. They can contain bacteria. The same applies to drinking water, which should not be drunk without a sanitation check.

When forecasting floods, storm tides and floods, meteorological factors are taken into account, as well as the movement of low pressure areas (cyclones and strong winds). The morphology of the coast is assessed, and the state of the water level according to the tide table is taken into account.

Finally

In addition to the above natural phenomena, there is also a fire (natural disaster or as a consequence of human activities), a tornado, a hurricane and a storm, which are extremely dangerous for human life. In order to prevent and protect yourself from the disaster, you need to strictly follow all the recommendations of experts and always be prepared for such natural disasters.