Natural phenomena are ordinary, sometimes even supernatural, climatic and meteorological events that occur naturally in all corners of the planet. It can be snow or rain familiar from childhood, or it can be incredible destructive or earthquakes. If such events take place away from the person and do not cause him material damage, they are considered unimportant. No one will draw attention to this. Otherwise, dangerous natural phenomena considered by mankind as natural disasters.
Research and observation
Characteristic natural phenomena people began to study in ancient times. However, it was possible to systematize these observations only in the 17th century, even a separate section of science (natural science) was formed that studies these events. However, despite many scientific discoveries, and to this day, some natural phenomena and processes remain poorly understood. Most often, we see the consequence of an event, and we can only guess and build about the root causes. various theories. Researchers in many countries are working on forecasting the occurrence, and most importantly, preventing their possible occurrence or at least reducing the damage caused by natural phenomena. And yet, despite all the destructive power of such processes, a person always remains a person and strives to find something beautiful, sublime in this. What natural phenomenon is the most fascinating? They can be listed for a long time, but, probably, such as a volcanic eruption, a tornado, a tsunami should be noted - they are all beautiful, despite the destruction and chaos that remain after them.
Weather phenomena of nature
Natural phenomena characterize the weather with its seasonal changes. Each season has its own set of events. So, for example, in the spring the following snowmelt, flood, thunderstorms, clouds, wind, rains are observed. V summer period the sun gives the planet an abundance of heat, natural processes at this time the most favorable: clouds, warm wind, rain and, of course, a rainbow; but can also be severe: thunderstorms, hail. In autumn they change, the temperature drops, the days become cloudy, with rain. During this period, the following phenomena prevail: fogs, leaf fall, hoarfrost, first snow. in winter vegetable world falls asleep, some animals hibernate. The most frequent natural phenomena are: freezing, snowstorm, blizzard, snow, on the windows appear
All these events are ordinary for us, we have not paid attention to them for a long time. Now let's look at the processes that remind humanity that it is not the crown of all, and the planet Earth has only sheltered it for a while.
Dangerous natural phenomena
These are extreme and severe climatic and meteorological processes that occur in all parts of the world, but some regions are considered more vulnerable to certain types of events than others. Hazardous natural phenomena become disasters when infrastructure is destroyed and people die. These losses represent major obstacles to human development. It is practically impossible to prevent such cataclysms; all that remains is timely forecasting of events in order to prevent casualties and material damage.
However, the difficulty lies in the fact that dangerous natural phenomena can take place on different scales and in different time. In fact, each of them is unique in its own way, and therefore it is very difficult to predict it. For example, flash floods and tornadoes are destructive but short-lived events affecting relatively small areas. Other dangerous disasters, such as droughts, can develop very slowly, but affect entire continents and entire populations. Such disasters last for several months, and sometimes even years. In order to monitor and predict these events, some national hydrological and meteorological services and special specialized centers are entrusted with the task of studying dangerous geophysical phenomena. This includes volcanic eruptions, airborne ash, tsunamis, radioactive, biological, chemical pollution, etc.
Now let's take a closer look at some natural phenomena.
Drought
The main reason for this cataclysm is the lack of rainfall. A drought is very different from other natural disasters in that it develops slowly, and its onset is often hidden. various factors. There are even recorded cases in world history when this disaster lasted for many years. Drought often has devastating consequences: first, water sources (streams, rivers, lakes, springs) dry up, many crops stop growing, then animals die, widespread realities become poor health and malnutrition.
Tropical cyclones
These natural phenomena are areas of very low atmospheric pressure over subtropical and tropical waters, forming a colossal rotating system of thunderstorms and winds hundreds (sometimes thousands) of kilometers across. The speed of surface winds in the zone of a tropical cyclone can reach two hundred kilometers per hour or even more. Interaction low pressure and wind-driven waves often result in a coastal storm surge, a huge volume of water thrown ashore with tremendous force and high speed, which washes away everything in its path.
Air pollution
These natural phenomena occur as a result of the accumulation in the air of harmful gases or particles of substances resulting from cataclysms (volcanic eruptions, fires) and human activities (work industrial enterprises, vehicles, etc.). Haze and smoke come from fires in undeveloped lands and forest areas, as well as burning the remains of agricultural crops and logging; Moreover, due to the formation volcanic ash. These atmospheric pollutants have very serious consequences for the human body. As a result of such cataclysms, visibility is reduced, there are interruptions in the operation of road and air transport.
desert locust
Such natural phenomena cause serious damage in Asia, the Middle East, Africa and the southern part of the European continent. When environmental and weather favor the reproduction of these insects, they are concentrated, as a rule, in small areas. However, with an increase in the number of locusts, it ceases to be an individual creature and turns into a single living organism. From small groups, huge flocks are formed, moving in search of food. The length of such a jamb can reach tens of kilometers. In a day, he can cover distances of up to two hundred kilometers, sweeping away all vegetation in his path. So, one ton of locusts (this is a small part of the flock) can eat as much food per day as ten elephants or 2500 people eat. These insects pose a threat to millions of pastoralists and farmers living in vulnerable environmental conditions.
Flash floods and flash floods
Data can occur anywhere after heavy rainfall. Any flood plains are vulnerable to floods, and violent storms cause flash floods. In addition, flash floods are sometimes even observed after periods of drought, when very heavy rains fall on a hard and dry surface through which water flow cannot seep into the ground. These natural events are characterized by the most various kinds: from violent small floods to a powerful layer of water that covers vast areas. They can be caused by tornadoes, severe thunderstorms, monsoons, extratropical and tropical cyclones(their strength can be increased by exposure to warm El Niño currents), melting snow and ice jams. V coastal areas as a result of tsunamis, cyclones or rising water levels in rivers, due to unusually high tides, storm surges often lead to flooding. The reason for the flooding of vast territories below the barrier dams is often the flood on the rivers, which is caused by melting snow.
Other natural hazards
1. Debris (mud) flow or landslide.
5. Lightning.
6. Extreme temperatures.
7. Tornado.
10. Fires on undeveloped lands or in forests.
11. Heavy snow and rain.
12. Strong winds.
The earth is fraught with many unusual and sometimes unexplained phenomena, and from time to time throughout the territory the globe various kinds of phenomena and even cataclysms occur, most of which can hardly be called ordinary and familiar to humans. Some cases have quite understandable reasons, but there are also those that even experienced scientists cannot explain for many decades in a row. True, natural disasters of this kind do not happen often, only a few times during the year, but, nevertheless, the fear of them in mankind does not disappear, but, on the contrary, grows.
The most dangerous natural phenomena
They include the following types disasters:
earthquakes
This is a dangerous natural phenomenon in the ranking of the most dangerous natural anomalies. Ground tremors of the earth's surface, arising in places of ruptures of the earth's crust, provoke vibrations that turn into seismic waves of considerable power. They are transmitted over considerable distances, but they become strongest near the immediate focus of shocks and provoke large-scale destruction of houses and buildings. Since there are a lot of buildings on the planet, the number of victims goes into the millions. Much has been affected by earthquakes more people in the world than from other cataclysms. Only in the last ten years from them in different countries more than 700,000 people died in the world. Sometimes the tremors reached such force that entire settlements were destroyed in an instant.
Tsunami waves
Tsunamis are natural disasters that cause a lot of destruction and death. Waves of great height and strength that arise in the ocean, or in other words, tsunamis, are the result of earthquakes. These giant waves usually in areas where seismic activity significantly increased. A tsunami moves very fast, and as soon as it gets aground, it begins to grow rapidly in length. As soon as this huge fast wave reaches the shore, in a matter of minutes it is able to demolish everything in its path. The destruction caused by a tsunami is usually large-scale, and people who are taken by surprise by the cataclysm often do not have time to escape.
Ball lightning
Lightning and thunder are familiar things, but such a type as ball lightning is one of the most terrible phenomena nature. Ball lightning is powerful electrical discharge current, and it can take absolutely any shape. Usually this type of lightning looks like luminous balls, most often reddish or yellow color. It is curious that these lightnings completely defy all the laws of mechanics, appearing out of nowhere, usually before a thunderstorm, inside houses, on the street, or even in the cockpit of an aircraft that is making a flight. Ball-shaped lightning hovers in the air, and does it very unpredictably: for a few moments, then it becomes smaller, and then completely disappears. It is strictly forbidden to touch ball lightning, it is also undesirable to move when meeting with it.
Tornadoes
This natural anomaly also belongs to the most terrible natural phenomena. Usually called a tornado air flow, which twists into a kind of funnel. Outwardly, it looks like a columnar cloud of a conical shape, inside which air moves in a circle. All objects that fall into the tornado zone also begin to move. The speed of the air flow inside this funnel is so huge that it can easily lift into the air very heavy objects weighing several tons and even houses.
sandstorms
This type of storm occurs in deserts due to strong winds. Dust and sand, and sometimes particles of soil carried by the wind, can reach several meters in height, and in the area where the storm has broken out, there will be a sharp deterioration in visibility. Travelers, caught in such a storm, risk dying, because the sand gets into the lungs and eyes.
Blood rains
This unusual natural phenomenon owes its threatening name to a strong water tornado that sucked red algae spores out of the water in reservoirs. When they mix with the water masses of the tornado, the rain takes on a terrible red hue, very reminiscent of blood. This anomaly was observed by the inhabitants of India for several weeks in a row, a rain of color human blood caused fear and panic in people.
fire tornadoes
Natural phenomena and natural disasters are most often unpredictable. Among them is one of the scariest fire tornado. This type of tornado is already dangerous, but , if it occurs in a fire zone, it should be feared even more. Near several fires, when a strong wind occurs, the air above the fires begins to heat up, its density becomes less, and it begins to rise along with the fire. At the same time, the air flows twist into a kind of spiral, and the air pressure acquires tremendous speed.
The fact that the most terrible natural phenomena are poorly predicted. Often they come suddenly, catching people and authorities by surprise. Scientists are working to create advanced technologies that can predict upcoming events. Today, the only guaranteed way to avoid the "whims" of the weather is only to move to areas where such phenomena are observed as rarely as possible or have not been recorded before.
Natural disasters natural character occur in Russia. Climatic anomalies determine the frequency and intensity of natural disasters of a hydrometeorological nature. Earthquakes, floods, droughts, hurricanes, snowfalls, downpours, tornadoes are most often noted in Russia. Often there are landslides, mudflows, avalanches. Regularly repeating tornadoes and squally winds in the central part of Russia clearly demonstrate the limited possibilities for their forecast and the low level of protection of the population. environmental impact are land flooding, pollution surface water, forest damage. For example, in 1997, 494 dangerous natural (natural) phenomena were noted on the territory of the Russian Federation, which is 95 more than in 1996. In 1997, 117 earthquakes and volcanic eruptions occurred, heavy precipitation (rain, snow, hail) - 103 , strong winds- 90 times. Understanding the number of natural hazards (NHEs) and emerging emergencies per last years gives the following table. 22.1.~~ In 1997, there were 360 emergency situations that were caused by natural hazards. Most often, weather conditions with heavy rain and wind, floods, floods led to emergencies. Table data. 22.1 show that with fluctuations in the number of natural hazards from 300 to 500 per year, there is a well-defined trend towards an increase in natural hazards leading to emergency situations. This upward trend in the number of annual emergencies is in good agreement with global statistics on the increase in the number of natural disasters. In 1997, 74 people died on the territory of the Russian Federation as a result of APY, and 45 people died in 1996.
Natural hazards refer to extreme climatic or meteorological phenomena occurring naturally at one point or another on the planet. In some regions such dangerous phenomena may appear with greater frequency and destructive force than in others. Dangerous natural phenomena develop into natural disasters when the infrastructure created by civilization is destroyed and the people themselves die.
1. Earthquakes
Among all natural hazards, the first place should be given to earthquakes. In places of breaks in the earth's crust, tremors occur, which cause vibrations of the earth's surface with the release gigantic energy. The resulting seismic waves are transmitted over very long distances, although these waves have the greatest destructive power in the epicenter of the earthquake. Due to strong fluctuations earth's surface massive destruction of buildings.
Since there are quite a lot of earthquakes, and the surface of the earth is quite densely built up, then total people in history who died as a result of earthquakes exceeds the number of all the victims of the rest natural disasters and number in the many millions. For example, for last decade Earthquakes have killed over 700,000 people around the world. From the most devastating shocks, entire settlements instantly collapsed. Japan is the most earthquake-affected country, and one of the most catastrophic earthquakes occurred there in 2011. The epicenter of this earthquake was in the ocean near the island of Honshu, according to the Richter scale, the magnitude of the shocks reached 9.1 points. Powerful aftershocks and the subsequent devastating tsunami disabled the nuclear power plant in Fukushima, destroying three of the four power units. Radiation covered a large area around the station, rendering densely populated areas so valuable in Japanese conditions uninhabitable. A colossal tsunami wave turned into a mess what the earthquake could not destroy. More than 16 thousand people officially died, among which another 2.5 thousand who are considered missing can be safely added. Only in this century have devastating earthquakes occurred in Indian Ocean, Iran, Chile, Haiti, Italy, Nepal.
2. Tsunami waves
A specific water disaster in the form of tsunami waves often results in numerous casualties and catastrophic destruction. As a result of underwater earthquakes or shifts of tectonic plates in the ocean, very fast, but hardly noticeable waves arise, which grow into huge ones as they approach the coast and enter shallow water. Most often, tsunamis occur in areas with increased seismic activity. A huge mass of water, rapidly moving ashore, blows everything in its path, picks it up and carries it deep into the coast, and then carries it into the ocean with a reverse current. Humans, unable to feel danger like animals, often do not notice the approach of a deadly wave, and when they do, it is too late.
A tsunami usually kills more people than the earthquake that caused it (the latter in Japan). In 1971, the most powerful tsunami ever observed occurred there, the wave of which rose 85 meters at a speed of about 700 km / h. But the most catastrophic was the tsunami observed in the Indian Ocean (the source is an earthquake off the coast of Indonesia), which claimed the lives of about 300 thousand people along a significant part of the coast of the Indian Ocean.
A tornado (in America this phenomenon is called a tornado) is a fairly stable atmospheric vortex, most often occurring in thunderclouds. He is a visa...
3. Volcanic eruption
Throughout its history, mankind has remembered many catastrophic volcanic eruptions. When the pressure of magma exceeds the strength of the earth's crust in the most weak points, which are volcanoes, it ends with an explosion and outpourings of lava. But the lava itself is not so dangerous, from which you can simply get away, as hot pyroclastic gases rushing from the mountain, pierced here and there by lightning, as well as a noticeable effect on the climate of the strongest eruptions.
Volcanologists count from five thousand dangerous active volcanoes, several dormant supervolcanoes, not counting the thousands of extinct ones. So, during the eruption of the Tambora volcano in Indonesia, the surrounding lands were plunged into darkness for two days, 92 thousand inhabitants died, and a cold snap was felt even in Europe and America.
List of some strong volcanic eruptions:
- Volcano Laki (Iceland, 1783). As a result of that eruption, a third of the population of the island died - 20 thousand inhabitants. The eruption lasted for 8 months, during which flows of lava and liquid mud erupted from volcanic cracks. The geysers have never been more active. Living on the island at that time was almost impossible. The crops were destroyed, and even the fish disappeared, so the survivors experienced hunger and suffered from unbearable living conditions. This may be the longest eruption in human history.
- Volcano Tambora (Indonesia, Sumbawa Island, 1815). When the volcano exploded, the sound of this explosion spread over 2,000 kilometers. Ash covered even the remote islands of the archipelago, 70 thousand people died from the eruption. But even today, Tambora is one of the highest mountains in Indonesia, retaining volcanic activity.
- Volcano Krakatoa (Indonesia, 1883). 100 years after Tambora, another catastrophic eruption occurred in Indonesia, this time "blowing the roof off" (literally) the Krakatoa volcano. After the catastrophic explosion that destroyed the volcano itself, frightening peals were heard for another two months. A huge amount of rocks, ash and hot gases were thrown into the atmosphere. The eruption was followed by a powerful tsunami with a wave height of up to 40 meters. These two natural disasters together they destroyed 34 thousand islanders along with the island itself.
- Volcano Santa Maria (Guatemala, 1902). After a 500-year hibernation in 1902, this volcano woke up again, starting the 20th century with the most catastrophic eruption, which resulted in the formation of a one and a half kilometer crater. In 1922, Santa Maria again reminded of itself - this time the eruption itself was not too strong, but a cloud of hot gases and ash brought death to 5 thousand people.
4. Tornadoes
Ecological disasters have their own specifics - during them not a single person may die, but at the same time a very significant amount will be inflicted ...
A tornado is a very impressive natural phenomenon, especially in the USA, where it is called a tornado. This is an air stream twisted in a spiral into a funnel. Small tornadoes resemble slender narrow pillars, and giant tornadoes can resemble a mighty carousel directed to the sky. The closer to the funnel, the stronger the wind speed, it begins to drag along ever larger objects, up to cars, wagons and light buildings. In the "tornado alley" of the United States, entire city blocks are often destroyed, people die. The most powerful vortices of category F5 reach a speed of about 500 km/h in the center. The state of Alabama suffers the most every year from tornadoes.
There is a variety fiery tornado, which sometimes occurs in the zone of massive fires. There, from the heat of the flame, powerful ascending currents are formed, which begin to twist into a spiral, like an ordinary tornado, only this one is filled with flame. As a result, a powerful draft is formed near the surface of the earth, from which the flame grows even stronger and incinerates everything around. When the catastrophic earthquake hit Tokyo in 1923, it caused massive fires that led to the formation of a fiery tornado that rose 60 meters. The column of fire moved towards the square with frightened people and burned 38 thousand people in a few minutes.
5. Sandstorms
This phenomenon occurs in sandy deserts when a strong wind picks up. Sand, dust and soil particles rise to a sufficiently high height, forming a cloud that dramatically reduces visibility. If an unprepared traveler gets into such a storm, he can die from grains of sand falling into the lungs. Herodotus described history as 525 BC. e. in the Sahara, a 50,000-strong army was buried alive by a sandstorm. In Mongolia, 46 people died as a result of this natural phenomenon in 2008, and two hundred people suffered the same fate the year before.
Throughout the history of mankind, the strongest earthquakes have repeatedly caused enormous damage to people and were the cause of huge number civilian casualties...
6. Avalanches
From the snow-covered mountain peaks, snow avalanches periodically descend. Climbers especially often suffer from them. During World War I, up to 80,000 people died from avalanches in the Tyrolean Alps. In 1679, five thousand people died in Norway from snowmelt. In 1886 there was major disaster, as a result of which the "white death" claimed 161 lives. The records of the Bulgarian monasteries also mention human sacrifices. snow avalanches.
7 Hurricanes
In the Atlantic they are called hurricanes, and in pacific ocean typhoons. These are huge atmospheric vortices, in the center of which the strongest winds and sharply reduced pressure are observed. A few years ago, the devastating Hurricane Katrin swept over the United States, which particularly affected the state of Louisiana and the densely populated city located at the mouth of the Mississippi. New Orleans. 80% of the city was flooded, killing 1836 people. famous destructive hurricanes steel also:
- Hurricane Ike (2008). The diameter of the eddy was over 900 km, and in its center the wind was blowing at a speed of 135 km/h. In the 14 hours that the cyclone moved across the United States, it managed to cause $30 billion worth of damage.
- Hurricane Wilma (2005). This is the largest Atlantic cyclone in the history of meteorological observations. A cyclone that originated in the Atlantic made landfall several times. The amount of damage inflicted by him amounted to $ 20 billion, 62 people died.
- Typhoon Nina (1975). This typhoon was able to breach China's Bankiao Dam, causing the dams below to collapse and causing catastrophic flooding. The typhoon killed up to 230,000 Chinese.
8. Tropical cyclones
These are the same hurricanes, but in tropical and subtropical waters, which are huge low-pressure atmospheric systems with winds and thunderstorms, often exceeding a thousand kilometers in diameter. Near the surface of the earth, winds in the center of the cyclone can reach speeds of over 200 km/h. Low pressure and wind cause the formation of a coastal storm surge - when colossal masses of water are thrown ashore at high speed, washing everything in their path.
Occasionally, tsunami waves occur in the ocean. They are very insidious open ocean completely invisible, but as soon as they approach the coastal shelf, g ...
9. Landslide
Prolonged rains can cause landslides. The soil swells, loses its stability and slides down, taking with it everything that is on the surface of the earth. Most often, landslides occur in the mountains. In 1920, the most devastating landslide occurred in China, under which 180 thousand people were buried. Other examples:
- Bududa (Uganda, 2010). Due to mudflows, 400 people died, and 200 thousand had to be evacuated.
- Sichuan (China, 2008). Avalanches, landslides and mudflows caused by an 8-magnitude earthquake claimed 20,000 lives.
- Leyte (Philippines, 2006). The downpour caused a mudflow and a landslide that killed 1,100 people.
- Vargas (Venezuela, 1999). Mudflows and landslides after heavy rains (almost 1000 mm of precipitation fell in 3 days) on the northern coast led to the death of almost 30 thousand people.
10. Fireballs
We are accustomed to ordinary linear lightning accompanied by thunder, but ball lightning is much rarer and more mysterious. The nature of this phenomenon is electrical, but scientists cannot yet give a more accurate description of ball lightning. She is known to have different sizes and shape, most often these are yellowish or reddish luminous spheres. For unknown reasons, ball lightning often ignores the laws of mechanics. Most often they occur before a thunderstorm, although they can appear in absolutely clear weather, as well as indoors or in the cockpit. The luminous ball hangs in the air with a slight hiss, then it can start moving in an arbitrary direction. Over time, it seems to shrink until it disappears altogether or explodes with a roar. But the damage ball lightning can bring very limited.
A geological hazard is an event that occurs as a result of the activity geological processes arising in the earth's crust under the influence of various geological or natural factors or a combination of them, and providing negative impact on plants, people, animals, natural environment, economic objects. Most often, geological phenomena are associated with the movement of lithospheric plates and changes occurring in the lithosphere.
Types of hazardous phenomena
Geological hazards include:
- talus and landslides;
- sat down;
- subsidence or dips of the earth's surface as a result of karst;
- kurums;
- erosion, abrasion;
- avalanches;
- flushes;
- landslides.
Each species has its own characteristics.
Landslides
Landslides are a geological hazard, which is a sliding displacement of rock masses along slopes under the influence of own weight. This phenomenon occurs as a result of slope erosion, due to seismic tremors, or under other circumstances.
Landslides occur on the slopes of hills and mountains, on steep river banks. They can be caused by a variety of natural phenomena:
- earthquakes;
- heavy rainfall;
- uncontrolled plowing of slopes;
- trimming slopes when laying roads;
- as a result of deforestation;
- during blasting;
- with abrasion and river erosion, etc.
Causes of landslides
Landslides are a dangerous geological phenomenon that most often occurs as a result of the impact of water. It seeps into cracks in the ground rocks, which causes destruction. All loose deposits are saturated with moisture: the resulting layer plays the role of a lubricant between the layers of earthen rocks. When the inner layers break, the detached mass begins to float down the slope, as it were.
Landslide classification
There are several types of dangerous geological phenomena, divided by the speed of movement:
- Very fast. They are characterized by the movement of masses at a speed of 0.3 m/min.
- Fast are characterized by the movement of masses at a speed of 1.5 m / day.
- Moderate - the landslide occurs at a speed of up to one and a half meters per month.
- Slow - the speed of movement - up to one and a half meters per year.
- Very slow - 0.06 m/year.
In addition to the speed of movement, all landslides are divided by size. According to this criterion this phenomenon subdivided as follows:
- grandiose, occupying an area of more than four hundred hectares;
- very large - the area of the landslide is about two hundred hectares;
- large - area - about a hundred hectares;
- small - 50 ha;
- very small - less than five hectares.
The thickness of a landslide is characterized by the volume of shifting rocks. This figure can reach several million cubic meters.
Mudflows
Another dangerous geological phenomenon is a mudflow, or mudflow. This is a temporary rapid mountain stream of water mixed with clay, sand, stones, etc. A mudflow is characterized by a sharp rise in the water level, which occurs in wave movements. Moreover, this phenomenon does not last long - for a couple of hours, but has a strong destructive effect. The area affected by a mudflow is called a mudflow basin.
For this dangerous geological natural phenomenon to occur, three conditions must be met simultaneously. Firstly, there should be a lot of sand, clay and stones of small diameter on the slopes. Secondly, to wash it all off the slope, you need a lot of water. Thirdly, mudflow can occur only on steep slopes, with an inclination angle of about twelve degrees.
Causes of mudflows
The occurrence of a dangerous mudflow can occur different reasons. Most often, this phenomenon is observed as a result of intense rains, rapid melting of glaciers, as well as as a result of tremors and volcanic activity.
Mudflow can occur as a result of human activities. An example of this is deforestation on the slopes of mountains, quarrying or mass construction.
snow avalanche
The snow avalanche also belongs to dangerous geological natural phenomena. During an avalanche, a mass of snow slides off the steep slopes of the mountains. Its speed can reach one hundred meters per second.
During the fall of an avalanche, an air pre-avalanche wave is formed, causing big damage nature and any objects erected on the path of the phenomenon.
Why is there an avalanche
There are several reasons why an avalanche begins. These include:
- intensive snow melting;
- long snowfall, which results in a large snow mass that is not able to stay on the slopes;
- earthquakes.
An avalanche can occur due to strong noises. This phenomenon is caused by fluctuations air environment, resulting from the sounds emitted at a certain frequency and with a certain force.
As a result of the snow avalanche, buildings are destroyed, engineering structures. Any obstacles in its path are destroyed: bridges, power lines, oil pipelines, roads. This phenomenon causes great damage agriculture. If there are people in the mountains when the snow melts, they may die.
Snow avalanches in Russia
Knowing the geography of Russia, you can accurately determine where the most dangerous avalanche areas are. The most dangerous areas are mountains with large quantity snow fall. This is Western and Eastern Siberia, Far East, Ural, and North Caucasus and mountains of the Kola Peninsula.
Avalanches account for about half of all accidents in the mountains. The most dangerous periods of the year are winter and spring. During these periods, up to 90% of snow masses are recorded. An avalanche can descend at any time of the day, but most often it snows during the day, and rarely in the evening. The impact force of the snow mass can be estimated at tens of tons per square meter! While driving, the snow sweeps away everything in its path. If a person fills up, then he will not be able to breathe, as the snow clogs Airways, penetrating the dust into the lungs. People can freeze, get severe injuries, frostbite internal organs.
collapses
And what other phenomena are related to geological hazards and what are they? These include crashes. These are detachments of large masses of rocks on river valleys, coast of the seas. Collapses occur due to the detachment of masses from the parent base. Landslides can block or destroy roads, cause overflows huge amount water from reservoirs.
Falls are small, medium and large. The latter include detachments of rocks weighing from ten million cubic meters. Medium-sized fragments include fragments with a volume of one hundred thousand to ten million cubic meters. The mass of small collapses reaches tens of cubic meters.
Crashes can occur as a result of features geological structure terrain, as well as cracks on the slopes of mountains. The cause of the formation of landslides can be human activities. This phenomenon is observed during the crushing of rocks, and also due to the large amount of moisture.
As a rule, collapses occur suddenly. Initially on rock a crack is formed. Gradually, it increases, causing a separation of the breed from the maternal formation.
earthquakes
When asked: "Indicate dangerous geological phenomena," the first thing that comes to mind is earthquakes. It is this species that is considered one of the most terrible, destructive manifestations of nature.
To understand the causes of this phenomenon, it is necessary to know the structure of the Earth. As you know, it has a hard shell - the earth's crust, or lithosphere, mantle and core. The lithosphere is not a whole formation, but several huge plates, as if floating on the mantle. These plates move, collide, overlap each other. Earthquakes occur in the zones of their interaction. However, shocks can appear not only along the edges of the plates, but also in their central part. Other reasons due to which shocks occur include volcanic eruptions, man-made factors. In some regions, seismic activity is clearly visible due to water fluctuations in the reservoir.
Earthquakes can result in landslides, subsidence, tsunamis, avalanches, and more. One of the dangerous manifestations is soil liquefaction. With this phenomenon, the earth is oversaturated with water, and with shocks lasting ten seconds or more, the soil becomes liquid and loses its bearing capacity. As a result of this, roads are destroyed, houses sag and collapse. One of clear examples this phenomenon is considered to be the liquefaction of the soil in 1964 in Japan. As a result of this event, several high-rise buildings slowly tilted. They didn't have any damage.
Another manifestation of tremors can be ground subsidence. This phenomenon occurs due to particle vibration.
Serious consequences of earthquakes can be ruptures of dams, as well as the occurrence of floods, tsunamis and more.
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