Disaster- a catastrophic natural phenomenon (or process) that can cause numerous human casualties, significant material damage and other grave consequences.
Natural disasters- these are dangerous natural processes or phenomena that are not amenable to human influence, which are the result of the action of the forces of nature. Natural disasters are catastrophic situations that, as a rule, occur suddenly, leading to disruption of the daily life of large groups of people, often accompanied by human casualties and destruction of property.
Natural disasters include earthquakes, volcanic eruptions, mudflows, landslides, avalanches, floods, droughts, cyclones, hurricanes, tornadoes, snow drifts and avalanches, prolonged torrential rains, severe persistent frosts, and extensive forest and peat fires. Natural disasters also include epidemics, epizootics, epiphytotics, and the massive spread of pests in forestry and agriculture.
Natural disasters can be caused by:
fast movement of matter (earthquakes, landslides);
release of intraterrestrial energy (volcanic activity, earthquakes);
rise in the water level of rivers, lakes and seas (floods, tsunamis);
exposure to unusually strong winds (hurricanes, tornadoes, cyclones);
Some natural disasters (fires, landslides, landslides) can occur as a result of human activities, but more often the forces of nature are the root cause of natural disasters.
The consequences of natural disasters can be severe. The greatest damage is caused by floods (40% of the total damage), hurricanes (20%), earthquakes and droughts (15% each), 10% of the total damage falls on other types of natural disasters.
Regardless of the source of occurrence, natural disasters are characterized by significant scales and varying duration, from a few seconds and minutes (earthquakes, avalanches) to several hours (mudflows), days (landslides) and months (floods).
Earthquakes- the most dangerous and destructive natural disasters. The area of occurrence of the underground impact is the focus of the earthquake, within which the process of releasing the accumulated energy takes place. In the center of the focus, a point, called the hypocenter, is conditionally highlighted. The projection of this point on the earth's surface is called the epicenter. During an earthquake, elastic seismic waves, longitudinal and transverse, propagate in all directions from the hypocenter. On the surface of the earth in all directions from the epicenter, surface seismic waves diverge. As a rule, they cover vast territories. The integrity of the soil is often violated, buildings and structures are destroyed, water supply, sewerage, communication lines, electricity and gas supply fail, there are human casualties. This is one of the most devastating natural disasters. According to UNESCO, earthquakes rank first in terms of economic damage and the number of human casualties. They appear unexpectedly, and although the duration of the main shock does not exceed a few seconds, their consequences are tragic.
Some earthquakes were accompanied by devastating waves that devastated the coast - tsunami... Now it is a generally accepted international scientific term, it comes from the Japanese word, which means "a big wave that floods the bay." The exact definition of a tsunami sounds like this - these are long waves of a catastrophic nature, arising mainly as a result of tectonic movements on the ocean floor. Tsunami waves are so long that they are not perceived as waves: their length ranges from 150 to 300 km. In the open sea, tsunamis are not very noticeable: their height is several tens of centimeters or at most several meters. Having reached the shallow shelf, the wave becomes higher, rises and turns into a moving wall. Entering shallow bays or funnel-shaped river mouths, the wave becomes even higher. At the same time, it slows down and, like a giant shaft, rolls onto land. The higher the depth of the ocean, the higher the tsunami speed. The speed of most tsunami waves fluctuates between 400 and 500 km / h, but there were cases when they reached 1000 km / h. Tsunamis occur most often as a result of underwater earthquakes. Volcanic eruptions can serve as another source.
Flood- temporary flooding of a significant part of the land with water as a result of the actions of the forces of nature. Floods can be caused by:
heavy rainfall or intense melting of snow (glaciers), the combined action of flood waters and ice jams; blowing wind; underwater earthquakes. Floods can be predicted: set the time, nature, expected size and timely organize preventive measures that significantly reduce damage, create favorable conditions for rescue and urgent emergency recovery operations. The land can be flooded by rivers or the sea - this is how river and sea floods differ. Floods threaten almost 3/4 of the earth's surface. According to UNESCO statistics, about 200,000 people died from river floods in 1947-1967. According to some hydrologists, this figure is even underestimated. Secondary damage from floods is even more significant than from other natural disasters. These are destroyed settlements, drowned cattle, dirt covered with mud. As a result of the torrential rains that took place in Transbaikalia in early July 1990, unprecedented floods occurred in these places. More than 400 bridges were demolished. According to the regional emergency flood commission, the national economy of the Chita region suffered 400 million rubles of damage. Thousands of people were left homeless. Not without human sacrifice. Floods can be accompanied by fires due to breaks and short circuits of electrical cables and wires, as well as ruptures of water supply and sewer pipes, electrical, television and telegraph cables located in the ground, due to the subsequent uneven soil settlement.
Mudflows and landslides... Mudflow is a temporary flow that suddenly forms in mountain river beds, characterized by a sharp rise in the water level and a high content of solid material in it. It occurs as a result of intense and prolonged downpours, rapid melting of glaciers or snow cover, and the collapse of a large amount of friable material into the channel. Having a large mass and speed of movement, mudflows destroy buildings, structures, roads and everything else on the way. Within the basin, mudflows can be local, general and structural. The former arise in the channels of the tributaries of rivers and large gullies, the latter pass along the main channel of the river. The danger of mudflows is not only in their destructive power, but also in the suddenness of their appearance. About 10% of the territory of our country is affected by mudflows. In total, about 6,000 mudflow streams have been registered, of which more than half are in Central Asia and Kazakhstan. According to the composition of the transferred solid material, mudflows can be muddy (a mixture of water with fine earth with a small concentration of stones), mud-stone (a mixture of water, pebbles, gravel, small stones) and water-stone (a mixture of water with mainly large stones). The speed of the mud flow is usually 2.5-4.0 m / s, but in case of a breakthrough of congestions, it can reach 8-10 m / s and more.
Hurricanes- these are winds with a force of 12 on the Beaufort scale, i.e. winds with a speed exceeding 32.6 m / s (117.3 km / h). Hurricanes are also called tropical cyclones that occur in the Pacific Ocean off the coast of Central America; in the Far East and in the Indian Ocean regions, hurricanes ( cyclones) are called typhoons... During tropical cyclones, wind speeds often exceed 50 m / s. Cyclones and typhoons are usually accompanied by intense torrential rains.
A hurricane on land destroys buildings, communication and power lines, damages transport communications and bridges, breaks and uproots trees; when spreading over the sea, it causes huge waves with a height of 10-12 m and more, damages or even leads to the death of the vessel.
Tornado- these are catastrophic atmospheric vortices in the form of a funnel with a diameter of 10 to 1 km. In this vortex, the wind speed can reach an implausible value - 300 m / s (which is more than 1000 km / h). This speed cannot be measured by any instruments; it is estimated experimentally and by the degree of impact of a tornado. For example, it was noted that during a tornado, a chip stuck into the trunk of a pine tree. This corresponds to wind speeds above 200 m / s. The process of a tornado is not fully understood. Obviously, they are formed at the moments of unstable air stratification, when the heating of the earth's surface leads to heating of the lower air layer. Above this layer is a layer of colder air, this situation is unstable. Warm air rushes upwards, while cold air in a vortex, like a trunk, descends down to the earth's surface. This often occurs over small, elevated areas within flat terrain.
Dust storms- these are atmospheric disturbances, in which a huge amount of dust and sand, transported over considerable distances, rises into the air. In comparison with earthquakes or tropical cyclones, dust storms are not, in fact, such catastrophic phenomena, but their impact can be very unpleasant and sometimes fatal.
Fires- spontaneous spread of combustion, manifested in the destructive effect of fire, out of the control of man. Fires occur, as a rule, when fire safety measures are violated, as a result of lightning discharges, spontaneous combustion and other reasons.
Forest fires - uncontrolled burning of vegetation, spreading over the forest area. Depending on in which elements of the forest the fire spreads, fires are subdivided into downstream, upstream, and underground (soil) fires, and depending on the speed of the fire edge and the height of the flame, fires can be weak, medium-strength and strong. Most often, fires are grassroots.
Peat fires most often they are in places where peat is mined, they usually arise due to improper handling of fire, from lightning strikes or spontaneous combustion. Peat burns slowly to the full depth of its occurrence. Peat fires cover large areas and are difficult to extinguish.
Fires in cities and towns occur when fire safety rules are violated, due to a malfunction of the electrical wiring, the spread of fire during forest, peat and steppe fires, when the electrical wiring is closed during earthquakes.
Landslides- these are sliding displacements of the masses of rocks down the slope, arising from imbalance caused by various reasons (undermining of rocks by water, weakening of their strength due to weathering or waterlogging by precipitation and groundwater, systematic shocks, unreasonable economic activities of a person, etc.). Landslides differ not only in the rate of displacement of rocks (slow, medium and fast), but also in their scale. The rate of slow displacements of rocks is several tens of centimeters per year, average - several meters per hour or per day, and fast - tens of kilometers per hour or more. Rapid displacements include landslides when solid material mixes with water, as well as snow and snow avalanches. It should be emphasized that only rapid landslides can cause fatal disasters. Landslides can destroy human settlements, destroy agricultural land, create a hazard during the operation of quarries and mining, damage communications, tunnels, pipelines, telephone and electrical networks, water facilities, mainly dams. In addition, they can block a valley, form a dam lake, and contribute to flooding.
Avalanches also refer to landslides. Large avalanches are disasters that claim dozens of lives. The avalanche speed ranges from 25 to 360 km / h. In terms of size, avalanches are divided into large, medium and small. Large ones destroy everything on their way - dwellings and trees, medium ones are dangerous only for people, small ones are practically not dangerous.
Volcanic eruptions threaten about 1/10 of the number of inhabitants of the Earth who are threatened with earthquakes. Lava is a melt of rocks heated to a temperature of 900 - 1100 "C. Lava flows directly from cracks in the ground or the slope of a volcano, or overflows the edge of a crater and flows to the foot. Lava flows can be dangerous for one person or a group of people who, underestimating their speed, they will find themselves between several lava tongues.Danger arises when a lava flow reaches settlements.Liquid lavas can flood large areas in a short period of time.
Every year, various human activities and natural phenomena cause environmental disasters and economic losses around the world. But beyond the dark side, there is something delightful about the destructive power of nature.
This article will present you the most interesting natural phenomena and cataclysms that happened in 2011 and 2012, and at the same time remained not particularly known to the public.
10. Sea smoke on the Black Sea, Romania.
Sea smoke is the evaporation of sea water, which occurs when the air is cold enough and the water is warmed up by the sun. Due to the temperature difference, the water starts to evaporate.
This beautiful photo was taken a few months ago in Romania by Dan Mihailescu.
9. Strange sounds emanating from the frozen Black Sea, Ukraine.
If you've ever wondered what a frozen sea sounds like, here's the answer! Reminiscent of scratching nails on wood.
The video was filmed on the coast of Odessa in Ukraine.
8. Trees in a spider web, Pakistan.
An unexpected side effect of the great flood that flooded one-fifth of Pakistan's landmass is that millions of spiders, fleeing the water, climbed trees and formed cocoons and huge webs there.
7. Fire tornado - Brazil.
A rare phenomenon called "fire tornado" was filmed in Aracatuba, Brazil. A deadly cocktail of heat, strong winds and fires formed a whirlwind of fire.
6. Shore of cappuccino, UK.
In December 2011, the Cleveleys seaside resort, Lancashire, was covered in cappuccino sea foam (first photo). The second and third photographs were taken in Cape Town, South Africa.
According to experts, sea foam is formed from fat and protein molecules created by the decomposition of tiny sea creatures (Phaeocystis).
5. Snow in the desert, Namibia.
As you know, the Namibian Desert is the oldest desert on earth, and it would seem that apart from sand and eternal heat, there can be nothing unusual here. However, according to statistics, snow falls here almost every ten years.
The last time it happened was in June 2011, when snow fell between 11 and 12 noon. On this day, the lowest temperature in Namibia was recorded -7 degrees Celsius.
4. Huge maelstrom, Japan.
An incredibly large whirlpool formed off the east coast of Japan after the tsunami hit last year. Whirlpools are common during tsunamis, but large eddies are rare.
3. Waterspouts, Australia.
In May 2011, four tornado-like tornadoes formed off the coast of Australia, one of which reached an altitude of 600 meters.
Waterspouts usually start as a tornado - over the ground, and then move to a body of water. Their height starts from a few meters, and their width ranges from one hundred meters.
It is noteworthy that the locals in this region have not seen such phenomena for over 45 years.
2. Massive sandstorms, USA.
This incredible video shows the huge sandstorm that swallowed Phoenix in 2011. The dust cloud grew up to 50 km wide and reached 3 km high.
Sandstorms are a common meteorological event in Arizona, but researchers and locals have unanimously stated that the storm was the largest in the state's history.
1. Volcanic ash of Lake Nahuel Huapi - Argentina.
The violent eruption of the Puyehue volcano - near the city of Osorno, in southern Chile has created an incredible sight in Argentina.
Northeast winds blew some of the ash onto Lake Nahuel Huapi. And its surface is covered with a thick layer of volcanic remnants, which are very abrasive and do not dissolve in water.
By the way, Nahuel Huapi is the deepest and cleanest lake in Argentina. The lake stretches for 100 km along the Chilean border.
The depth reaches 400 meters, and its area is 529 sq. km.
Devastating tsunamis in Asia in 2004 and 2011, hurricane Katrina in the southeastern United States of America in 2005, landslides in the Philippines in 2006, earthquake in Haiti in 2010, flooding in Thailand in 2011 ... This list can be continued for a long time ...
Most natural disasters are the result of the laws of nature. Hurricanes, typhoons and tornadoes are the result of various weather phenomena. Earthquakes occur as a result of changes in the earth's crust. Tsunamis are caused by underwater earthquakes.
Typhoon - a type of tropical cyclone, which is typical for the northwestern part of the Quiet Ocean. The word comes from Chinese. The zone of typhoon activity, which accounts for a third of the total number of tropical cyclones on Earth, is enclosed between the coast of East Asia in the west, the equator in the south and the date line in the east. Although a considerable part of typhoons occurs from May to November, other months are also not free from them.
The typhoon season of 1991 was especially destructive, as soon a number of typhoons with a pressure of 870-878 bar raged off the coast of Japan. Typhoons are carried to the shores of the domestic Far East, in most cases, after Korea, Japan and Ryukyu Islands. The Kuril Islands, Sakhalin, Kamchatka and Primorsky Territories are more prone to typhoons. Many managed to record the typhoon in Novorossiysk on personal photo and video cameras, mobile phones.
Tsunami. Long high waves generated by a powerful impact on the entire water column in the ocean or other body of water. Most tsunamis are caused by underwater earthquakes, during which there is an abrupt displacement (raising or lowering) of a section of the seabed. Tsunamis are formed during an earthquake of any strength, but those that arise due to strong earthquakes (with a magnitude of more than 7) reach great strength. As a result of an earthquake, several waves propagate. More than 80% of tsunamis occur on the periphery of the Pacific Ocean.
Note that quite recently the Japanese company Hitachi Zosen Corp has developed a tsunami barrier system that automatically reacts to the impact of a wave. At the moment, it is known that the barriers will be installed at the entrances to the underground parts of buildings. In the normal state, the metal walls lie on the surface of the earth, however, during the arrival of the wave, they rise under the pressure of the advancing water and take a vertical position. The height of the fence is only one meter, ITAR-TASS reports. The system is completely mechanical and does not require any external power source. A number of coastal cities in Japan are currently operating similar barriers, but they are powered by electricity.
Tornado (tornado). A hurricane is an extremely fast and strong, often destructive and long-lasting movement of air. A tornado (tornado) is a vortex horizontal movement of air that occurs in a thundercloud and descends to the surface of the earth in the form of an overturned funnel, the diameter of which is up to hundreds of meters. Usually, the transverse diameter of a tornado funnel in the lower section is 300-400 m, although if the tornado touches the water surface, this value can be only 20-30 m, and when the funnel passes over the land, it can reach 1.5-3 km. The development of a tornado from a cloud distinguishes it from some outwardly similar and also different in nature phenomena, for example, tornado-vortices and dust (sand) vortices.
Tornadoes very often occur in the United States. As recently as May 19, 2013, a devastating tornado in Oklahoma affected about 325 people. Eyewitnesses speak with one voice: “We thought we were going to die because we were in the basement. The wind tore out the door and pieces of glass and debris began to fly at us. To be honest, we thought we were going to die. " The wind speed reached 300 kilometers per hour, more than 1.1 thousand houses were destroyed.
Earthquakes- tremors and vibrations of the Earth's surface caused by natural causes (usually tectonic processes), or artificial processes (explosions, filling of reservoirs, collapse of underground cavities of mine workings). Small tremors can also be caused by the rise of lava during volcanic eruptions. There are about a million earthquakes on the entire Earth every year, but most of them are so minor that they go unnoticed. Strong destructive earthquakes occur on the planet about once every two weeks. Most of them occur at the bottom of the oceans and are not accompanied by catastrophic consequences (unless a tsunami occurs).
In our country, Kamchatka is a particularly seismically active zone. The other day, on May 21, 2013, she again found herself in the epicenter of seismic events. Seismologists have recorded a series of earthquakes with a magnitude of 4.0 to 6.4 off the southeastern coast of the peninsula. The centers of earthquakes lay at a depth of 40-60 kilometers under the seabed. The tremors were most noticeable in Petropavlovsk-Kamchatsky. In total, according to experts, more than 20 underground disturbances were registered. Fortunately, there was no tsunami threat.
Natural disasters were still described in the distant past, for example, the "global flood" described in the Bible. Floods are common and can become truly global. For example, the flood in 1931 on the Yangtze River in China flooded an area of 300 thousand km², and in some areas the water remained for four months.
The death of the cities of Sodom and Gomorrah described in the Bible, according to scientists, resembles a natural phenomenon - an earthquake. Researchers of Atlantis are inclined to believe that the island was also flooded as a result of an earthquake. During the eruption of Mount Vesuvius, the cities of Herculaneum and Pompeii were buried under a layer of ash. The resulting tsunami may be the result of earthquakes and volcanic eruptions. The eruption of the Krakatoa volcano in 1833 was accompanied by an earthquake. As a result, a tidal wave was formed, which reached the shores of the islands of Java and Sumatra. The death toll was about 300 thousand people.
Natural disasters annually take about 50 thousand lives. Since 1970, new data has been added to the statistics. During the earthquake in America in 1988, according to various estimates, between 25 and 50 thousand people died. Nine out of ten natural disasters are of four types. Floods account for 40%, tropical cyclones 20%, earthquakes and droughts 15%. Tropical cyclones rank among the leaders in terms of the number of victims. Floods cause great material damage. According to R. Cates, the annual damage caused by natural disasters to the world economy is about US $ 30 billion.
Natural disasters are destructive natural processes that cause injury and death.
To study natural disasters, you need to know the nature of each of them. Natural disasters in the form of a tropical cyclone carry the danger of extreme action of all its elements: rain, wind, waves, storm surges. The most destructive are storm surges.
In 1970, in the northern part of the Bay of Bengal, a tropical cyclone caused the sea level to rise by six meters. This led to flooding. As a result of the devastating hurricane and the flooding that began, about 300 thousand people died, agriculture suffered $ 63 million in damage. 60% of the population was killed, mainly fishermen, 65% of fishing vessels were destroyed. The consequences of the disaster affected the supply of protein food to the entire region.
Tropical cyclones are seasonal. On average, up to 110 incipient hurricanes are traced over the Atlantic from satellites per year. But only 10-11 of them will grow to gigantic proportions. It is necessary to predict the onset of a tropical cyclone in time in order to protect people. Hurricanes are first identified and then tracked from satellites. If a hurricane threat is detected, its path and speed are predicted. The speed and direction of a tropical cyclone can be determined 300 kilometers away by radar. It is very important to identify the area of the coast where the storm surge may start, as well as the signs of a tornado. Weather services constantly inform the public about the location and characteristics of the cyclone.
Floods are natural disasters that flood coastal areas. The initial stage of flooding begins with overflowing the channel and overflowing the banks. Flooding is the most common natural phenomenon. Floods can occur in permanent and temporary watercourses, but even where there have never been rivers and lakes, for example, in areas where there is heavy rainfall.
Densely populated areas of the Earth suffer from floods: China, India, Bangladesh. Flooding in China occurs in the valleys of the Yellow and Yangtze rivers. Despite centuries of experience and hundreds of dams, the population of these areas still falls victim to floods. Severe flooding in the lower Yangtze River in the 20th century caused 60 million people to suffer from famine. During the flood in 1911, 100 thousand people were killed.
Floods are still a big threat today. After heavy downpours in 1952, the English resort town of Lynmouth was flooded. The flood destroyed buildings, flooded the streets, and uprooted trees. Large numbers of people vacationing at Linmouth were cut off from solid ground. The next day, the dam burst and 34 people died.
There is an inverse relationship between property damage due to flooding and the number of casualties. Countries with more to lose have every means to prevent or mitigate flooding. Conversely, pre-industrial countries suffer more property damage, but do not have the necessary means to prevent disaster and save people. Flooding can lead to outbreaks of infectious diseases. To combat flooding, dams and dams are being built, reservoirs are being built to collect flood waters, and river beds are deepening.
Earthquakes are natural disasters caused by the sudden release of the energy of the earth's interior in the form of shock waves and vibrations. An earthquake is dangerous due to direct and secondary effects. Direct manifestations, due to seismic waves and tectonic movements, cause soil displacement. Secondary effects are the cause of subsidence, soil compaction. As a result of secondary effects, cracks are formed on the earth's surface, tsunamis, avalanches, and fires. A powerful earthquake is always accompanied by a large number of human casualties and material losses. According to statistics, the largest number of victims of this disaster falls on China, the USSR, Japan, Italy. An earthquake kills approximately 14,000 people every year. Zones of destruction from the epicenter of an earthquake can be several tens and hundreds of kilometers. For example, the epicenter of the 1985 earthquake in Mexico was in the Pacific Ocean, near the city of Acapulco. But despite this, it was so powerful that a significant part of the country suffered, especially the capital of Mexico - Mexico City. On the Richter scale, the impact strength reached 7.8 points. Located 300 kilometers from the epicenter, about 250 buildings were destroyed in Mexico City, 20 thousand people were injured. The devastated zone during the earthquake in Guatemala spread 60 kilometers from the epicenter. The ancient capital of Antigua was completely destroyed, 23 thousand people died, 95% of settlements were destroyed.
Natural disasters are very difficult to predict. At the moment, scientists can predict powerful seismic shocks, but cannot indicate the exact time. But there were times when scientists were able to accurately predict an earthquake. In the Chinese province of Liaoning in 1974, local residents noticed signs of tectonic activity. The area was constantly monitored by geologists, who, after the first aftershocks on February 1, 1975, were able to predict the possibility of a devastating earthquake. The authorities took measures to evacuate the population, and four days later an earthquake began, which damaged 90% of the buildings. According to forecasts of experts, the number of victims could reach 3 million people, but thanks to the measures taken, large casualties were avoided.
Up to 2 billion people continue to live in earthquake-prone areas. Resettlement from seismically active zones is a radical measure to preserve the life and health of people.
Volcanic eruptions are natural disasters that have caused the death of 200 thousand people in 500 years. Until now, millions of people live in close proximity to volcanoes. On the island of Martinique in 1902, during a volcanic eruption, the city of Saint Pierre was destroyed, which was located 8 kilometers from the Mont Pele volcano. The death toll was about 28 thousand people. This is almost the entire population of the city of Saint Pierre. The activity of this volcano was already noted in 1851, but then there were no casualties and destruction. Experts predicted that this eruption would be similar to the previous one 12 days before the start of the eruption, so none of the residents attached great importance to the beginning of the approaching disaster.
In 1985, the Ruiz volcano in Colombia "woke up". This volcanic eruption resulted in a huge number of casualties and property damage. Most affected was the city of Amero, which was located 40 kilometers from Ruiz. The molten lava and gases melted the ice and snow at the top of the mountain, causing a mudflow that completely destroyed the city. Killed 15 thousand people, residents of the city of Amero. 20 thousand hectares of agricultural plantations, highways were destroyed, other settlements were destroyed. The total death toll was 25 thousand people, about 200 thousand were injured.
Natural disasters in the form of volcanic activity cause as much harm as in previous centuries. However, scientists managed to establish the size of the zones of influence of volcanoes. A lava flow spreads over a distance of up to 30 kilometers during large eruptions. Acidic and hot gases pose a threat within a radius of several kilometers. Acid rain, which spreads up to 400-500 kilometers, causes burns in people, poisoning of vegetation and soil.
Natural disasters need to be studied in order to develop a system of measures to protect human health and prevent massive loss of life. The engineering and geographic zoning of natural disaster zones is of great importance.
Classification of natural disasters. Natural disasters are divided into two types according to their origin:
1.endogenous - associated with the internal energy and forces of the Earth (volcanic eruptions, earthquakes, tsunamis);
2. exogenous - caused by solar energy and activity, atmospheric, hydrodynamic and gravitational processes (hurricanes, cyclones, floods, storms).
Causes of natural disasters. One of the causes of natural disasters is a natural disaster, a natural phenomenon that leads to the destruction of material assets, death of people and other consequences.
The main types of natural disasters:
1. Geological
· Earthquake
Earthquake - tremors and vibrations of the earth's surface resulting from sudden displacements and ruptures in the earth's crust and upper mantle and transmitted over long distances.
· Eruption
A volcanic eruption is a volcanic activity in which volcanic lava and hot gases are ejected to the surface. In addition to the direct eruption of the volcano, great damage is caused by the ejection of volcanic ash and pyroclastic flows (a mixture of volcanic gases, stones, ash).
An avalanche is a mass of snow or ice that falls or slides off steep mountain slopes. Particularly destructive avalanches can completely destroy populated areas.
A collapse is the separation of rock masses from the slope and rapid movement downward. They arise on the banks of rivers, seas, in the mountains under the influence of precipitation, seismic shocks, human activity
Landslide
Landslide - the separation of earth masses from the slope and their movement along the slope under the influence of gravity.
Mudflow is a powerful mud, mud-stone or water-stone stream that forms in the beds of mountain rivers due to a sharp flood caused by heavy rainfall, snow melting and other reasons.
2. Meteorological
Hail is a type of precipitation in the form of dense ice particles (hailstones) of irregular shapes of various sizes.
Drought is prolonged dry weather, often at elevated air temperatures, with no or very little atmospheric precipitation, leading to depletion of moisture reserves in the soil and a sharp decrease in the relative humidity of the air.
Blizzard - the transfer of snow by the wind over the surface of the earth.
Tornado is an extremely strong atmospheric vortex with air circulation closed around a more or less vertical axis.
A cyclone is an atmospheric vortex with reduced pressure in the middle and air circulation in a spiral.
3. Hydrological
· Flood
Flood - flooding of an area with water.
Tsunamis are very long sea waves that occur during strong underwater and coastal earthquakes, as well as during volcanic eruptions or large rock falls from a coastal cliff.
Limnological disaster
A limnological disaster is a rare natural phenomenon in which carbon dioxide dissolved in deep lakes is released to the surface, causing asphyxiation of wild and domestic animals and people.
4. Fires
· Forest fires
Forest fires - spontaneous or human-induced ignition in forest ecosystems
Peat fires
Peat fires - burning of a layer of peat and tree roots.
The impact of space objects on the Earth is distinguished into a separate group of causes of natural disasters: collisions with asteroids, falling meteorites. They pose a great threat to the planet, since even a small celestial body in a collision with the Earth can cause devastating damage.
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