What is a natural disaster? Natural disasters and their classification

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:40

A natural disaster is a destructive phenomenon with great power, causing significant damage to the territory in which it occurs. In the process of a catastrophe of this type, a lot of damage is done. These can be: earthquakes, tsunamis, landslides, droughts, floods, tornadoes, hurricanes and more.

Classification of natural disasters

Natural emergencies, or natural disasters, in Russia and other countries are usually classified as follows:

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

• hurricanes;
• storms;
• squalls;
• tornadoes;
• vertical eddies;
• frost;
• tornado;
• showers;
• snowfalls;
• drought;
• blizzards;
• mists, etc.

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

For example, even the strongest earthquakes that occurred in a vast uninhabited area are not considered significant disasters, unlike weaker shocks that occurred in densely populated regions.

Earthquakes

These are the most formidable and natural disasters in terms of the amount of damage caused, as well as the number of victims. In addition, it is quite difficult to protect yourself from such catastrophes, since even taking into account the fact 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 of 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 make it possible to pick up even the weakest shocks that cannot be felt.

In 1935, C. Richter created a scale that made it easy to calculate and compare the power of underground vibrations. In fact, an American seismologist improved the invention of the Japanese scientist Wadachi. According to this 12-point scale, earthquakes are classified according to their power today.

Prediction and protection

There are three typesforecast: amateur, professional or scientific. There have been times when sensitive people have made extremely accurate earthquake predictions.

The main methods for predicting disasters of this type are:

1. Detection of seismically active zones.
2. Studying changes in the composition of gases that come from the depths.
3. The study of the slightest changes in the ratio of the speed and duration of tremors.
4. Studying 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 thanks to the developed protection measures. They are developed by the competent authorities specializing in the study of seismically hazardous regions in Russia.

What to do during an earthquake?

First of all, you should remain calm, as panic can only aggravate the situation. If you are outdoors, try to stay away from billboards and high point objects. People who run out of their homes in search of safer shelters are most at risk. It's actually best to stay indoors with all electrical appliances turned off. It is strictly forbidden to enter the elevator during an earthquake. Such natural disasters begin as suddenly as they end, but nevertheless, after the last tremor, it is recommended to leave the shelter no earlier than 40 minutes.

Tsunami

The name "tsunami" comes froma Japanese word that means "big wave washing away the bay." The scientific definition of this natural disaster is as follows - these are long waves of a catastrophic nature, resulting mainly from the movement of tectonic plates on the ocean floor.

Thus, we can say that this disaster is natural and is most often caused by an earthquake. Tsunami waves can reach lengths of 150 to 300 kilometers. In the open sea, such fluctuations are practically imperceptible. 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 demolish entire coastal cities. If the wave hits shallow bays or river mouths, it becomes even higher. In the same way that an earthquake is measured, there is a special scale that allows you to characterize the intensity of a tsunami.

• I - The tsunami is very weak. The wave is almost imperceptible, it is noted only by tide gauges.
• II – The tsunami is weak. Can flood flat coasts.
• III - Tsunami of medium strength. Floods flat coasts and can also wash light ships ashore.
• IV - Strong tsunami. Completely floods the coast and damages coastal buildings and other structures. Throws large sailing ships and small motor boats onto land.
• V - Very strong tsunami. All coastal areas are flooded, and structures are severely damaged. Larger vessels are washed ashore, and damage is also caused inlandcoast. With a very strong tsunami, most often there are human casu alties. Such a natural disaster is quite common, and thousands of people suffer from it every year.
• VI - Catastrophic tsunami. The coast and coastal areas are completely devastated. The land and a significant area inland are completely flooded. Makes many sacrifices.

Prediction and protection

In the center of the Hawaiian Islands, in Honolulu, there is a special tsunami warning service. The organization processes data from the 31st seismic station, as well as records from more than 50 tide gauges. Among other things, the institution studies such natural disasters and emergencies. The service can predict the appearance of a tsunami as early as 15-20 minutes before the event. Thus, the message must be transmitted immediately so that all necessary security measures can be taken.

In order to protect yourself from a tsunami, you should remain calm, just as in the case of earthquakes. It is necessary to move as far as possible 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 houses. In fact, the force of the wave can be so crushing that it will easily wipe out even the most stable object from the face of the earth. Tsunami is a natural and extremely dangerous disaster.

Volcanic eruptions

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

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

Lava flows are also a pretty serious threat. Despite the fact that the mass seems to be moving quite slowly, it is worth considering the fact that high temperatures give rise to hot air currents that can threaten human life even at a great distance.

Prediction 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 significantly.

Today, natural disasters such as "eruption" are eliminated thanks to artificial gutters that allow hot streams to be diverted. A rather effective method is the construction of safety dams.

Besides this, 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. If the volcanic ash is saturated with water, it begins to resemble liquid porridge, which canroll downhill at high speed. It is almost impossible to protect yourself from these mud flows, as they move quite quickly, and most often there is simply no time left 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.

Weaker mudflows can be protected from by dams or specially designed gutters. In some Indonesian settlements, residents lay out artificial hills at the foot of the volcano. During a natural event that threatens a serious danger, the settlers climb these mounds and thus avoid the hot mud flows.

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

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

The only protection against such gases is a gas mask.

Landslides

These phenomena are formed when natural processes (or, as most often happens, people) violate the stability of the slope.

At the moment when the force of the rocks becomes less than the force of gravity, the entire earth mass begins to move. Sometimes such massesslide down 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 considered to be an event that occurred in 1911 in the Pamirs in Russia. A giant landslide was triggered by an earthquake. According to the researchers, more than 2.5 cubic kilometers of loose material slid that day. The village of Usoy and all 54 inhabitants were completely littered. Such catastrophic types of natural disasters occur quite often not only in Russia, but also in many other countries.

If we talk about the number of victims, the most terrible landslide was a natural disaster that 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 filled up the Kansu valley, all its cities and villages. More than 200,000 people are estimated to have died.

Prediction and protection

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

But unfortunately, when the landslide has already begun, any protection methods become ineffective. According to studies, the main cause of landslides is water, so the first stage of conservation work is to collect and remove excess moisture.

Predictsuch natural phenomena are quite difficult, since in this case the amount of precipitation does not affect the formation of landslides, just like the atmosphere. Natural disasters of this type can occur unexpectedly and result from earthquakes.

Snow avalanches

The largest snow avalanches have killed more than 10,000 people in the last decade. The fact is that the flow rate can vary from 25 to 360 km / h. There are three types of avalanches: large, medium and small.

Big ones demolish almost everything in their path, easily wipe villages and other objects from the face of the earth. Medium ones are dangerous only for people, since they are not able to destroy buildings. Small avalanches are practically not dangerous and, in principle, invisible to humans.

Prediction and protection

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

In order to predict the approach of an 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 100 mm of fresh snow falling, there is the highest probability of an avalanche in a few hours.

For disaster protection, avalanche slopesprotected by protective shields. If it was not possible to stop the elements, shelling of the snowy slopes is carried out. This provokes the gathering of smaller and less dangerous masses.

Floods and natural disaster - flooding

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

Similar natural disasters that occurred between 1947 and 1967 killed more than 200,000 people. For residents of Russia, this issue is very relevant. For example, St. Petersburg has been flooded 245 times. The largest of them took place in 1824, and was even described by A. S. Pushkin in the poem "The Bronze Horseman". The fact is that the city is located at the bottom of the coastal plain, and as soon as the water rises by 150 cm, moisture begins to seep.

Prediction and protection

Natural disaster - flooding and its prevention requires compliance with land use rules and proper development of settlements. By regulating the flow of rivers and protecting the surrounding areas, the threat of flooding can be reduced to a minimum. It can also be stable barrier dams that provide full or partial protection. In order to implement long-term protection from natural disasters, it is necessary to provide regular care and control of coastal zones.

The main factor responsible for the intensity of floods is the amount of precipitation. For this, morphological and biologicalfactors.

Today, the World Emergency Commission has developed special instructions in case of floods and floods. Let's get acquainted with the most important of them.

1. Before the flood, you need to prepare sandbags and clean the sewers, as well as provide yourself with energy sources. It is important to stock up on drinking water and food. Disaster cleanup of this kind can take quite a long time.
2. During a flood, low-lying places should be avoided, which, in the end, may be flooded. It is necessary to move very carefully. If the water is above the knees, in no case should you cross the flooded areas. It is visually impossible to estimate the strength of the flow.
3. After a flood, do not eat food that has been soaked by flood waters. They may contain bacteria. The same applies to drinking water, which should not be drunk without sanitation.

When forecasting floods, storm surges 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 is also taken into account according to the tide table.

In conclusion

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

In order to prevent and protect yourself from disaster, you must strictly follow all the recommendations of experts and always be prepared for such natural disasters.