Natural disaster is a destructive phenomenon that has tremendous power and causes significant harm to the territory in which it occurs. In the process of a disaster of this type, great damage is done. It can be: earthquakes, tsunamis, landslides, droughts, floods, tornadoes, hurricanes and much more.
Natural disaster classification
Natural emergencies, or natural disasters, in Russia and other countries are usually classified as follows:
- Geological phenomena.
- Infectious diseases of people.
- Hydrological phenomena.
- Infectious diseases of livestock.
- Geophysical hazards.
- Damage to agricultural plants by pests and diseases.
- Natural fires.
- Marine hydrological phenomena.
- Meteorological and agrometeorological phenomena:
- hurricanes
- storms;
- squalls;
- tornadoes;
- vertical vortices;
- frost
- tornado;
- showers;
- snowfalls;
- drought;
- blizzards;
- fogs etc.
Types of natural disasters are characterized by the magnitude of the disaster, as well as the number of victims and the size of the damage caused, and not the area of the destroyed territory.
For example, even the most severe earthquakes that occurred in a vast uninhabited area do not belong to significant disasters, in contrast to the 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 in the number of victims. In addition, it is quite difficult to protect oneself from such disasters, 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, experts record the waves and vibrations of underground slabs. Modern electronic devices make it possible to pick up even the weakest shocks that cannot be felt.
In 1935, C. 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 Wadati. According to this 12-point scale, earthquakes are subdivided according to their power today.
Forecasting and Protection
There are three types of forecast: amateur, professional or scientific. There have been times when it was sensitive people who made extremely accurate predictions about earthquakes.
The main methods for predicting disasters of this type are:
- Identification of seismically active zones.
- The study of changes in the composition of gases that come from the depths.
- Investigation of the slightest changes in the ratio of speed and duration of tremors.
- Study of the distribution of foci in space and time.
- Studies of the magnetic field, as well as the electrical conductivity of rocks.
The consequences of natural disasters are prevented thanks to the developed protective measures. They are developed by competent authorities specializing in the study of seismically dangerous regions in Russia.
What to do during an earthquake?
First of all, you should remain calm, since panic can only aggravate the situation. If you are outside, try to stay away from billboards and high point features. People who run out of homes in search of more reliable shelters are most at risk. In fact, it is best to stay indoors by 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 earthquake, it is recommended to leave the shelter no earlier than 40 minutes later.
Tsunami
The name “tsunami” comes from the Japanese word for “big wave washing off the bay”. The scientific definition of this natural disaster is as follows - these are 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 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 almost 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 enters the shallow bays or at the mouths of the rivers, it becomes even higher. In the same way as an earthquake is measured, there is a special scale that allows you to characterize the intensity of the tsunami.
- I - The tsunami is very weak. The wave is almost imperceptible, it is noted only by tide gauges.
- II - The tsunami is weak. May 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 buildings and other structures. Throws on land large sailing ships and small motor boats.
- V - A very strong tsunami. All coastal territories are flooded, and structures are severely damaged. Larger vessels are thrown ashore, and damage is also caused in the interior of the coast. With a very strong tsunami, there are often human casualties. Such a natural disaster is quite common, and thousands of people suffer from it every year.
- VI - The catastrophic tsunami. The coast and coastal areas are completely devastated. The land and considerable space inland are completely flooded. It brings a lot of sacrifices.
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 mareographic posts. Among other things, the institution is studying such natural disasters and emergencies. Service can predict the occurrence of a tsunami at the earliest 15-20 minutes before the incident. Thus, the message must be transmitted immediately in order to manage to take all the necessary security measures.
In order to protect yourself from the tsunami, you should remain calm, as in the case of earthquakes. It is necessary to move away from the coastal strip as far as possible 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 devastating that it will easily erase even the most stable object from the face of the earth. The tsunami is a natural and extremely dangerous disaster.
Volcanic eruptions
Volcanic eruptions are characterized by volcanic processes that can cause a disaster. 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 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 volcanic eruptions are extremely dangerous for humans.
Lava flows are also quite a serious threat. Despite the fact that the mass seems to be moving rather slowly, it is worth considering the fact that high temperature creates hot air currents that can threaten a person’s 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 flows is significantly slowed down.
To date, natural disasters such as "eruptions" are eliminated thanks to artificial gutters that allow you to divert hot streams. A fairly effective method is the construction 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 ash layers are in a rather unstable position. If volcanic ash is saturated with water, it begins to resemble liquid porridge, which can roll off a slope with great speed. It is almost impossible to protect oneself from these mud flows, since they move quite quickly, and more often than not 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.
You can protect yourself from weaker mud flows by dams or specially designed gutters. In some Indonesian settlements, residents lay artificial hills at the foot of the volcano. During a natural phenomenon that poses a serious danger, settlers climb these mounds and thus avoid hot mud flows.
Another danger is that while glaciers melt from volcanic eruptions, they form a huge amount of water. This can lead to severe floods in the future. Thus, disasters and natural disasters can provoke each other.
Volcanic gases are also dangerous. They contain impurities of sulfur dioxide, 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 in the case when natural processes (or, as most often happens, people) violate the stability of the slope.
At that moment, when the force of the rocks becomes less than the force of gravity, the entire earth mass begins to move. Sometimes such masses creep along the slopes almost imperceptibly. But in some cases, their speed 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. A giant landslide was triggered by an earthquake. According to researchers, more than 2.5 cubic kilometers of loose material crawled 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 overwhelmed 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 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, disaster, 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 the collection and disposal 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 does the atmosphere. Natural disasters of this type can occur unexpectedly and become the result of earthquakes.
Snow avalanches
The largest snow avalanches have caused the death of more than 10, 000 people in the last decade. The fact is that the flow rate can range from 25 to 360 km / h. Avalanches come in three types: large, medium and small.
Large demolish almost everything in its path, easily erase villages and other objects from the face of the earth. The 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.
Forecasting and Protection
As in other situations, the most important role in protecting is played by preventive measures. Experts quite easily determine the avalanche-hazardous slopes and most often the elimination of the consequences of natural disasters is not needed. In addition, most avalanches descend along the same tracks.
In order to predict the approach of an avalanche, the wind direction and the amount of precipitation are studied in detail. If snow fell 25 mm thick, then there is a small likelihood of such an element. If the height is 55 mm, then the possibility of an avalanche increases. And when 100 mm of fresh snow falls, there is the greatest likelihood of an avalanche falling in a few hours.
To protect against natural disasters, avalanche-hazardous slopes are protected by protective shields. If it was not possible to stop the elements, shelling of the snowy slopes is carried out. This provokes the descent of small 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.
More than 200, 000 people died from such natural disasters that occurred between 1947 and 1967. 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 A. S. Pushkin in the poem “The Bronze Horseman”. The fact is that the city is located below the coastal plain, and as soon as the water rises 150 cm, the seepage of moisture begins.
Forecasting and Protection
Natural disaster - flooding and its prevention requires compliance with the rules of land use and proper development of settlements. By adjusting river flows and protecting surrounding areas, flood risk can be reduced to a minimum. It can also be stable barrier dams that provide full or partial protection. In order to provide long-term protection from natural disasters, it is necessary to provide regular care and control of coastal zones.
The main factor responsible for flood intensity is the amount of rainfall. For this, morphological and biological factors are also investigated.
To date, the World Commission for Emergency Situations has developed special guidelines for floods and floods. Let's get acquainted with the most important of them.
- Before the flood, it is necessary to prepare sandbags and clean the sewer, as well as provide yourself with energy sources. It is important to stock up on drinking water and food. Disaster management of such a plan can take quite a while.
- During floods, low locations should be avoided, which could ultimately be flooded. It is necessary to move extremely carefully. If the water is above the knees, in no case should you cross the flooded areas. It is visually impossible to evaluate the strength of the flow.
- After the flood, do not eat foods that have been soaked in flood waters. They may contain bacteria. The same applies to drinking water, which should not be drunk without a sanitary 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 coastal morphology is estimated, and the state of the water level is taken into account according to the tidal table.
