Why are landslides coming down. Landslides and landslides: types, causes, characteristics, protection against landslides and landslides. The main external signs of a landslide slope

Landslides, mudflows and avalanches are classified as dangerous geological phenomena.

In 1911. in the Pamirs, an earthquake caused a giant landslide. About 2.5 billion cubic meters of soil slumped. The village of Usoy with its inhabitants was overwhelmed. The landslide blocked the valley of the Murgab River, and the resulting dammed lake flooded the village of Saraz. The height of this formed dam reached 300 m, the maximum depth of the lake is 284 m, and the length is 53 km. Such large-scale disasters are rare, but the troubles are incalculable.

Landslides - this is the displacement of the masses rocks downhill by gravity.

Landslides are formed in various rocks as a result of imbalance, weakening of strength. They are caused by both natural and artificial (anthropogenic) causes. Natural causes include an increase in the steepness of slopes, undermining their foundations by sea and river waters, seismic shocks, etc. Artificial causes are the destruction of slopes by road excavations, excessive soil removal, deforestation, improper agricultural practices on slopes, etc. According to international statistics up to 80% of modern landslides are associated with anthropogenic factor... They can also arise from earthquakes. Landslides occur at a slope steepness of 10 ° or more. On clayey soils, with excessive moisture, they can also appear at a steepness of 5-7 °.

Landslides are classified according to the scale of the phenomenon, activity, mechanism and power of the landslide process, and the place of formation.

By scale landslides are classified as large, medium and small-scale.

Large Landslides are usually caused by natural causes and form along the slopes for hundreds of meters. Their thickness reaches 10-20 m and more. The landslide body often retains its solidity.

Medium and small scale landslides are smaller and are typical for anthropogenic processes.

The extent of landslides is characterized by the area involved. In this case, they are subdivided into grandiose - 400 hectares and more, very large - 200-400 hectares, large - 100-200 hectares, medium - 50-100 hectares, small - 5-50 hectares and very small - up to 5 hectares.

By activity landslides can be active and inactive. Their activity is determined by the degree of capture of the bedrock of the slopes and the speed of movement, which can range from 0.06 m / year to 3 m / s.

By the mechanism of the landslide process landslides are subdivided into shear landslides, extrusion, viscoplastic, hydrodynamic carryover, sudden liquefaction. Landslides often show signs of a combined mechanism.

By place of education landslides are subdivided into mountain, underwater, snow and artificial earth structures (pits, canals, rock heaps).

By power landslides can be small, medium, large and very large. They are characterized by the volume of displaced rocks, which can range from hundreds to 1 million m 3. A variety of landslides are avalanches. They are a mixture of snow and air crystals. Large avalanches occur on slopes of 25-60 °. They cause great damage and loss of life.

Mudflows (mudflows)- This is a turbulent mud or mud-stone flow that suddenly appears in the beds of mountain rivers.

The immediate causes of the onset of mudflows are heavy rainfall, washing out of water bodies, intense melting of snow and ice, as well as earthquakes and volcanic eruptions. The emergence of mudflows is also facilitated by anthropogenic factors, which include deforestation and degradation of soil cover on mountain slopes, explosions of rocks during road construction, overburden work in quarries, improper organization of dumps and increased air pollution, which has a detrimental effect on the soil and vegetation cover.

When driving, the mudflow is a continuous stream of mud, stones and water. Mudflows can carry individual fragments of rocks weighing 100-200 tons or more. The leading front of the mudflow wave forms the mudflow “head”, the height of which can reach 25 m.

Mudflows are characterized by linear dimensions, volume, speed of movement, structural composition, density, duration and repeatability. In areas with rainfall and snow supply, mudflows can be repeated several times during the year, but more often once every 2-4 years. Powerful mudflows are observed once every 10-12 years or more.

Mudflows are subdivided according to the composition of the transported material, the nature of movement and power.

By the composition of the transferred material distinguish between:

Mud streams - a mixture of water, fine earth and small stones;

Mud-stone streams - a mixture of water, fine earth, gravel, pebbles and small stones;

Water-stone streams are a mixture of water with large stones.

By the nature of the movement The mudflows are subdivided into connected and disconnected streams. Connected streams consist of a mixture of water, clay, sand and represent a single plastic substance... Such mudflow, as a rule, does not follow the bends of the channel, but straightens them. Disjointed streams are composed of water, gravel, pebbles and stones. The stream follows the bend of the channel at high speed, exposing it to destruction.

By power mudflows are subdivided into catastrophic, powerful, medium and low power.

Catastrophic mudflows are characterized by the removal of material over 1 million m 3. They happen on the globe once every 30-50 years. Powerful mudflows are characterized by the removal of material with a volume of 100 thousand m 3. Such mudflows are rare. With mudflows of weak thickness, the removal of material is insignificant and amounts to less than 10 thousand m 3. They appear annually.

Consequences of landslides, mudflows, landslides. Landslides, mudflows, avalanches cause great damage to the national economy, the natural environment, and lead to human casualties.

The main damaging factors landslides, mudflows and avalanches are impacts of moving masses of rocks, as well as the flooding and filling of previously free space by these masses. As a result, buildings and other structures are destroyed, settlements and objects are hidden by rock strata National economy, forest land, blocking of river beds and overpasses, death of people and animals, change in the landscape.

Landslides, mudflows and avalanches on the territory of the Russian Federation take place in mountainous areas North Caucasus, Ural, Eastern Siberia, Primorye, Sakhalin Islands, Kuril Islands, The Kola Peninsula, as well as along the banks of large rivers.

Landslides, mudflows and avalanches are classified as dangerous geological phenomena.

In 1911. in the Pamirs, an earthquake caused a giant landslide. About 2.5 billion cubic meters of soil slumped. The village of Usoy with its inhabitants was overwhelmed. The landslide blocked the valley of the Murgab River, and the resulting dammed lake flooded the village of Saraz. The height of this formed dam reached 300 m, the maximum depth of the lake is 284 m, and the length is 53 km. Such large-scale disasters are rare, but the troubles are incalculable.

Landslides are the movement of rock masses downhill due to gravity.

Landslides are formed in various rocks as a result of imbalance, weakening of strength. They are caused by both natural and artificial (anthropogenic) causes. Natural reasons include an increase in the steepness of slopes, undermining their foundations by sea and river waters, seismic shocks, etc. Artificial causes are the destruction of slopes by road excavations, excessive soil removal, deforestation, improper agricultural practices on slopes, etc. According to international statistics up to 80% of modern landslides are associated with an anthropogenic factor. They can also arise from earthquakes.

Landslides occur at a slope steepness of 10 ° or more. On clayey soils, with excessive moisture, they can also appear at a steepness of 5-7 °.

Landslides are classified according to the scale of the phenomenon, activity, mechanism and power of the landslide process, and the place of formation.

In terms of scale, landslides are divided into large, medium and small-scale.

Large Landslides are usually caused by natural causes and form along the slopes for hundreds of meters. Their thickness reaches 10-20 m and more. The landslide body often retains its solidity.

Medium and small scale landslides are smaller and are typical for anthropogenic processes.

The extent of landslides is characterized by the area involved. In this case, they are subdivided into grandiose - 400 hectares and more, very large - 200-400 hectares, large - 100-200 hectares, medium - 50-100 hectares, small - 5-50 hectares and very small - up to 5 hectares.

In terms of activity, landslides can be active and inactive. Their activity is determined by the degree of capture of the bedrock of the slopes and the speed of movement, which can range from 0.06 m / year to 3 m / s.

The activity is influenced by the rocks of the slopes, which form the basis of the landslide, as well as the presence of moisture. Depending on the quantitative indicators of the presence of water, landslides are divided into dry, slightly moist, wet and very wet.

According to the mechanism of the landslide process, landslides are subdivided into shear landslides, extrusion, viscoplastic, hydrodynamic carryover, and sudden liquefaction. Landslides often show signs of a combined mechanism.

According to the place of formation, landslides are subdivided into mountain, underwater, snow and artificial earth structures (pits, canals, rock dumps).

In terms of thickness, landslides can be small, medium, large and very large. They are characterized by the volume of displaced rocks, which can range from hundreds to 1 million m 3. A variety of landslides are avalanches. They are a mixture of snow and air crystals. Large avalanches occur on slopes of 25-60 °. They cause great damage and loss of life. So, on July 13, 1990, at Lenin Peak in the Pamirs, as a result of an earthquake, a large avalanche demolished the camp of climbers, located at an altitude of 5300 m. 48 people were killed. It was the biggest tragedy of Russian mountaineering.

Mudflows (mudflows). On June 8, 1921, at 24 o'clock, a mass of earth, silt, stones, snow, sand fell on the city of Alma-Ata from the side of the mountains, driven by a mighty stream of water. This stream demolished the dacha buildings located at the foot of the mountains, along with people, animals, orchards. A terrible stream burst into the city, turning its streets into raging rivers with steep banks from ruined houses. Houses along with their foundations were torn down and carried away by a stormy stream. The result was great loss of life and huge material damage. The cause of the mudflow is heavy rainfall in the upper part of the Malaya Almaatinka river basin. The total volume of mud-stone mass of 2 million m 3 cut the city with a 200-meter lifeless strip. This is just Mudflow is a turbulent mud or mud-stone flow that suddenly appears in the beds of mountain rivers.

The immediate causes of the onset of mudflows are heavy rainfall, washing out of water bodies, intense melting of snow and ice, as well as earthquakes and volcanic eruptions. The emergence of mudflows is also facilitated by anthropogenic factors, which include deforestation and degradation of soil cover on mountain slopes, explosions of rocks during road construction, overburden work in quarries, improper organization of dumps and increased air pollution, which has a detrimental effect on the soil and vegetation cover.

one example of the trouble a mudflow can bring.

When driving, the mudflow is a continuous stream of mud, stones and water. Mudflows can carry individual fragments of rocks weighing 100-200 tons or more. The leading front of the mudflow wave forms the mudflow “head”, the height of which can reach 25 m.

Mudflows are characterized by linear dimensions, volume, movement speed, structural composition, density, duration and repeatability.

The length of mudflow channels can range from several tens of meters to several tens of kilometers. The width of the mudflow is determined by the width of the channel and ranges from 3 to 100 m.The depth of the mudflow can be from 1.5 to 15 m.

The volume of the mudflow mass can be equal to tens, hundreds of thousands and millions of cubic meters.

The speed of movement of mudflows in individual sections of the channel has a different value. On average, it ranges from 2 to 10 m / s and more.

The duration of the movement of mudflows is most often 1-3 hours, less often - 8 hours or more.

The frequency of mudflows is different depending on different mudflow hazardous areas. In areas with rainfall and snow supply, mudflows can be repeated several times during the year, but more often once every 2-4 years. Powerful mudflows are observed once every 10-12 years or more.

Mudflows are subdivided according to the composition of the transported material, the nature of movement and power.

The composition of the transferred material is distinguished:

Mud streams - a mixture of water, fine earth and small stones;

Mud-stone streams - a mixture of water, fine earth, gravel, pebbles and small stones;

Water-stone streams are a mixture of water with large stones.

By the nature of the movement, mudflows are subdivided into connected and disconnected flows. Connected streams consist of a mixture of water, clay, sand and represent a single plastic substance. Such mudflow, as a rule, does not follow the bends of the channel, but straightens them. Disjointed streams are composed of water, gravel, pebbles and stones. The stream follows the bend of the channel at high speed, exposing it to destruction. By capacity, mudflows are subdivided into catastrophic, powerful, medium and low power.

Catastrophic mudflows are characterized by the removal of material over 1 million m 3. They happen on the globe once every 30-50 years.

Powerful mudflows are characterized by the removal of material with a volume of 100 thousand m 3. Such mudflows are rare.

With mudflows of weak thickness, the removal of material is insignificant and amounts to less than 10 thousand m 3. They appear annually.

Landfalls (mountain landslide)- separation and catastrophic fall of large masses of rocks, their overturning, crushing and rolling on steep and steep slopes.

Landslides natural origin observed in the mountains, on the seashores and on the cliffs of river valleys. They occur as a result of the weakening of the connectivity of rocks under the influence of the processes of weathering, washing away, dissolution and the action of gravity. The formation of landslides is facilitated by: geological structure terrain, the presence of cracks and zones of rock crushing on the slopes.

Most often (up to 80%) modern landslides are associated with an anthropogenic factor. They form mainly due to improper work, during construction and mining.

The landslides are characterized by the power of the landslide process (the volume of falling rock masses) and the scale of manifestation (involvement of the area in the process).

According to the power of the landslide process, landslides are subdivided into large (detachment of rocks with a volume of 10 million m 3), medium (up to 10 million m 3) and small (less than 10 million m 3).

According to the scale of manifestation, landslides are subdivided into huge (100-200 hectares), medium (50-100 hectares), small (5-50 hectares) and small (less than 5 hectares).

Consequences of landslides, mudflows, landslides. Landslides, mudflows, avalanches cause great damage to the national economy, the natural environment, and lead to human casualties.

The main damaging factors of landslides, mudflows and landslides are impacts of moving masses of rocks, as well as the flooding and filling of previously free space by these masses. As a result, buildings and other structures are destroyed, populated areas, objects of the national economy, forest lands are hidden by rock strata, river beds and overpasses are blocked, people and animals die, and the landscape changes.

In particular, these dangerous geological phenomena threaten the safety of the movement of railway trains and other land transport in mountainous areas, destroy and damage bridge supports, rails, road surfaces, power lines, communications, oil pipelines, hydroelectric power plants, mines and others industrial enterprises, mountain villages, vacations.

Significant damage is done agriculture... Mudflows lead to flooding and blockages of agricultural crops with debris on areas of hundreds and thousands of hectares. The arable land below the landslide areas is often waterlogged. At the same time, there are crop losses and an intensive process of land retirement from agricultural use.

These phenomena can cause significant damage to the cultural and historical heritage of peoples inhabiting mountainous areas.

The magnitude of the consequences is determined by:

The size of the population trapped in the landslide zone;

The number of dead, wounded and homeless;

The number of settlements included in the zone natural disaster;

The number of objects of the national economy, health-improving and socio-cultural institutions, which were destroyed and damaged;

Flooded and flooded areas of agricultural land;

The number of dead farm animals.

The secondary consequences of these natural disasters are emergencies associated with the destruction of technologically hazardous facilities, as well as the interruption of economic and vaccination activities.

Landslides, mudflows and avalanches on the territory of the Russian Federation take place in the mountainous regions of the North Caucasus, the Urals, Eastern Siberia, Primorye, Sakhalin Island, the Kuril Islands, the Kola Peninsula, as well as along the banks of large rivers.

Landslides often lead to large-scale catastrophic consequences. Thus, the landslide of 1963 in Italy with a volume of 240 million m 3 covered 5 cities, killing 3 thousand people in the process.

In 1989, landslides in Checheno-Ingushetia caused damage in 82 settlements of 2518 houses, 44 schools, 4 kindergartens, 60 health care, culture and consumer services.

In 1985. In Colombia, as a result of the eruption of the Ruiz volcano, a giant mudflow arose, which swept the city of Armero, as a result of which 22 thousand people died and 4.5 thousand residential and administrative buildings were destroyed.

In 1982, a mudflow 6 km long and up to 200 m wide hit the villages of Shiveya and Arenda in the Chita region. Houses, bridges, 28 estates were destroyed, 500 hectares of cultivated areas were washed away and brought in, people died.

Landslide - sliding and detachment of rock masses down the slope under the action of gravity.

According to the power of the landslide process, that is, the involvement of rock masses in the movement, landslides are divided into

Small - up to 10 thousand cubic meters,

Medium - 10-100 thousand cubic meters,

Large - 100-1000 thousand cubic meters,

· Very large - over 1000 thousand cubic meters.

The surface on which the landslide breaks off and moves downward is called the slip or displacement surface; by its steepness they are distinguished:

B) gentle (5 ° -15 °);

B) steep (15 ° -45 °).

By the depth of the sliding surface, landslides are distinguished:

Surface - not deeper than 1 m - mudslides, alloys;

Small - up to 5 m; deep - up to 20 m;

Very deep - deeper than 20 m.

Called by:

1.increase in the slope steepness as a result of water washout;

2. the weakening of the strength of rocks during weathering or waterlogging by precipitation and groundwater;

3. the impact of seismic shocks;

4. construction and economic activities.

Collapse- separation and fall of the masses of rocks down from the slopes of the mountains under the influence of gravity.

Landslides occur on the slopes of river banks and valleys, in the mountains, on the shores of the seas.

The cause of the formation of landslides is an imbalance between the shear force of gravity and the holding forces. It is caused by the same reasons as landslides.

Landfalls are:

1. large - weight 10 million m3 or more;

2. average - mass from several hundred to 10 million m3;

3. small - several tens of cubic meters.

Anti-landslide measures, in which the population should take part, are surface water diversion, tree planting, installation of various supporting engineering structures, extraction of trenches in order to drain the soil of the landslide massif, unloading and leveling of the landslide slope.

In addition, the population living in landslide-prone areas should not allow abundant water leakage from taps, damaged water pipes or water taps; it is necessary to temporarily arrange drainage drains when surface water accumulates (with the formation of puddles).

Tunnels and dams are built to protect against landslides and avalanches.

Mudflows: types, reasons, characteristics, protection against mudflows.

The main types of mudflows: water-stone; mud; mudstone.

Mudflows are characterized by linear dimensions (length and width), movement speed, duration and power (volume).

By power (volume) mudflows are subdivided into catastrophic, powerful, medium and low power.

Catastrophic mudflows are characterized by the removal of more than 1 million cubic meters of material. m, most often formed as a result of earthquakes and volcanic eruptions.

Powerful mudflows are characterized by the removal of material from 100 thousand to 1 million cubic meters. m and are rare.

With mudflows of medium thickness, material removal is observed from 10 to 100 thousand cubic meters. m and occur once every 2-3 years.

With mudflows of weak power, the removal of material does not exceed 10 thousand cubic meters. m and arise annually, sometimes several times a year.

Mudflow classification.

Classification of mudflows according to the height of their sources. Classification of mudflows by composition.

Anti-mudflow measures can be divided into two main groups: agromeliorative and hydraulic engineering (engineering).

The first group includes activities carried out in the catchment area: improvement forestry including afforestation; correct plowing of slopes (across) and their tinning; slope terracing and organization of surface runoff.

Hydraulic engineering measures are the most rational, and they are carried out by influencing the formed mudflow, since anti-erosion measures carried out on the slopes are not always effective and cannot stop the entire surface flow. Therefore, part of it falls into the channel, it is able to carry a large number of hard material and can cause significant damage to cities and found items.

Debris flow structures (popuzapond, spurs) are arranged to protect the bottom and banks of the channel from erosion or to protect any structures located along the river.

Mud-retaining structures are dams, damming up sediment traps. In the fight against mudflows, mudflow dams are widely used, which are ways to hold back large volumes of mudflow.

Snow avalanches: types, characteristics, protection against snow avalanches.

By the nature of the movement and depending on the structure of the avalanche center, the following three types are distinguished: trough, axial, jumping.

The trough moves along a specific drain channel or an avalanche tray.

Wasp is a snow landslide, does not have a definite runoff channel and slides over the entire width of the site.

Leaping arises from troughs where there are sheer walls or areas of steeply increasing steepness. Having met a steep ledge, the avalanche breaks off the ground and continues to move through the air in the form of a huge jet. Their speed is especially great.

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If you are caught in an avalanche

The main thing is not to panic. Remember: your life is in your hands. Many people caught in the avalanche remained safe and sound because they fought.

Try to stay on the surface, and for this throw skis, sticks, backpack; try to break out of the main channel to the edge of the avalanche with swimming movements.

Cover your nose and mouth from snow (for example, with a scarf or hood), do not take deep breaths.

If possible, try to catch on stationary objects.

When the avalanche stops, create around the head and chest air space- First of all, squeeze the snow out of your face.

If you've watched an avalanche

Remember the place where you saw people. Examine the surface for signs of a person (debris from equipment, scraps of clothing). Often the victim is near the discovered things.

If there are enough people in your group, start search and rescue work immediately.

Large piles of snow, places of turns, eddies are the most likely places for people to be in an avalanche.

Having found a person, free his mouth and nose from the snow, warm him.

When carrying out rescue operations, do not forget about your own safety.

The striking effect of snow avalanches on engineering structures, equipment, people is determined by their main characteristics: size, speed of movement, impact force, throw range, frequency of avalanches and density of avalanche snow.

The dimensions of an avalanche are characterized by volume (m3) or mass (t). Depending on the amount of snow involved in the movement, the volume (mass) of an avalanche can vary from several tens of cubic meters (tons) to several million cubic meters (tons) of snow / 77 /. The destructive power of such avalanches is different. An avalanche with a volume of 10 m3 poses a danger to humans and light equipment. Large avalanches are able to destroy capital engineering structures, it is difficult or insurmountable blockages to form on transport routes. The volume of an avalanche is estimated by direct measurements on the ground or from aerospace and aerovisual data using snow meteorological observations. The simplest calculations can be performed based on the data taken from the topographic map.

Speed ​​is one of the main characteristics of a moving avalanche; here the speed of movement of the avalanche front and the speed of the current behind the front are taken into account. For snow avalanche calculations, the most important speed in the frontal section (avalanche speed), the value of which can reach 50-100 m / s.

The force of the impact directly determines the magnitude of the impact of the avalanche on objects in the area of ​​its action; it can be 40 t / m3, and in the presence of an avalanche of foreign inclusions in the body - up to 200 t / m2. The frontal impact of avalanche snow on the obstacle is replaced by the flow pressure if the avalanche does not stop in front of the obstacle. Many dry avalanches are accompanied by a snow-dust cloud, sometimes avalanches are preceded by air shock waves; the impact of an air wave and a snow-dust cloud is similar to the impact of an air wave in explosions. The shock of water-saturated avalanche flows is similar to the hydraulic shock, which is calculated in the same way as the shock saturated with air liquid or mudflow mass.

Determination of the throw range is one of the main tasks of assessing the possibility of hitting objects located in avalanche-hazardous zones. Distinguish between the maximum throw and the most probable. Maximum range avalanche ejection (the distance that an avalanche can overcome under all conditions conducive to this focus) is determined taking into account the height of its fall. The most probable throw range is specified according to actual data directly on the ground. This is necessary when placing structures in the area of ​​avalanches (Fig. 2.1).

Distinguish between the average annual and intra-annual (seasonal) frequency of avalanches. The first is defined as the frequency of avalanches in a given avalanche center on average over a long-term period. Intra-annual is the frequency of avalanches in an avalanche center during the winter and autumn periods. In some areas during the winter and spring, avalanches can occur 15-20 times.

The density of avalanche snow is one of the most important physical parameters of avalanches; the force of the avalanche impact, labor costs for clearing and the ability to move along the surface of the avalanche depend on it. For avalanches from dry snow, the density is -200-400 kg / m3, for wet snow - 300-800 kg / m3. When planning the regime of human activity in an avalanche-prone area, the potential period of avalanche formation is taken into account - the time interval between the first and last avalanches in a given area during the year (season).

Protection against avalanches.

Permanent safeguards include effective and durable structures, support fences where an avalanche could start, separation or braking fences along the path of an avalanche, and blocking fences at the lowest point of avalanche descent.

The purpose of temporary protective measures is to create a safe and stable environment for avalanche-prone areas by deliberately provoking small avalanches to remove hazardous amounts of snow piece by piece.

Snowy avalanches, stormy sat down, insidious landslides ... All these natural phenomena are associated with mountainous terrain and can pose a significant danger to both people and their homes, roads, bridges and other objects. What is it?

snow avalanche is a mass of snow sliding off steep mountain slopes and moving at a speed of up to 30 meters per second. It's almost impossible to run away from her. The greatest destruction is produced not even by the avalanche itself, but by the air wave that "runs" in front of it. The avalanches can be caused by the intense melting of snow accumulated during the winter, an earthquake and a nearby explosion that shake the slopes. In Russia, avalanches most often occur in the North Caucasus, the Urals, in the mountains of Eastern Siberia and Of the Far East... Avalanche hazardous places are under the constant control of special services, which from time to time provoke artificial avalanches (warning the population about this), build protective structures and carry out rescue work.

It is curious that such a formidable phenomenon as an avalanche often becomes the subject of inspiration for poets. "... Avalanches go one after another, and behind the rockfall the rockfall roars ...", - Vladimir Vysotsky sang. And how many lines where avalanches are mentioned in the poems of Yuri Vizbor! Artists can poeticize danger, but in ordinary life it is best avoided.

To avoid being hit by an avalanche one should not go to the mountains in snowfall and bad weather, be aware of avalanche-prone slopes (steep more than 30 degrees), do not cross narrow ravines surrounded by steep "sides". The most avalanche-prone periods are spring and summer (from 10 am to sunset). If you spot an avalanche that hit high in the mountains, quickly get out of its way to safety or take cover behind a high rock. If it is impossible to leave, free yourself from all things, accept horizontal position(head towards the avalanche), tucking your knees to your stomach, cover your nose and mouth with a mitten, scarf or collar. Once in an avalanche, try to "swim" with it, keeping as close to its edge as possible. Try to create space around your chest and face to breathe. Don't scream - it's useless: the snow completely absorbs sounds, and screaming and meaningless movements weaken you and deprive you of oxygen. If an avalanche fell asleep in you, do not despair: save your energy and do not let yourself fall asleep - there have been cases when people were dug out from under the avalanche even 5-10 days after the incident.

What is mudflow? This is a temporary stream of water carrying large amounts of clay and rock debris of various sizes. Such a flow sometimes suddenly appears in river beds and mountain hollows of the North Caucasus, some regions of Eastern Siberia and the Far East. Mudflows occur after heavy rains, intense melting of snow and glaciers, as well as after an earthquake or volcanic eruption. The height of a mudflow wave can reach 15-20 meters, and the roar of a stormy stream can be heard for tens of kilometers. Places where mudflows can occur, and the possible time of their formation are usually known. Mountain rescuers warn tourists and local population about this danger. In dangerous areas, anti-mudflow dams and dams are being built, the level of mountain lakes is lowered, the slopes are strengthened by planting shrubs and trees on them. You can escape from the mudflow only if you manage to avoid it. Hearing the sound of an approaching stream, you must immediately climb the slope to a height of at least 80-100 meters from the bottom of the ravine. If you are hit by a stone thrown out of a mudflow, give yourself first aid, as with any injury: apply a bandage, ice, and after returning to the village, see a doctor.

Landslide is called the displacement (sliding) of the soil along the side of a mountain or on the side of a ravine, a steep coast of a sea, lake or river. Landslides happen when water erodes a slope or rocks become too wet. Landslides can be caused by earthquake, explosion or human activity. Landslide is not always instantaneous: sometimes the earth moves along the slope at a speed of several meters per year, gradually destroying the terrain. Landslides are a threat to houses, pipelines, roads; they can also cause death of people, as happened in the summer of 2005 on one of the "wild" beaches of Crimea. The study of landslides and the prediction of their occurrence are engaged in by scientists and workers of special stations. You, being in the danger zone, can learn about the threat of a landslide by jamming the doors and windows of the building, water seepage from the slope. If you feel that something is wrong, inform the EMERCOM employees about it, and act according to the situation yourself. After a landslide has occurred, do not enter the damaged house without making sure that there is no threat of collapse. Do not turn on the light and gas, check if the gas line and wiring are not damaged.

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LANDSLIDES.
Landslides are sliding displacements of rock masses down a slope under the influence of gravity. They occur on the slopes of mountains, ravines, hills, on the banks of rivers.

Landslides occur when natural processes or people disturb the stability of the slope. The forces of binding of soils or rocks are at some point less than the force of gravity, the whole mass starts to move and a catastrophe may occur.

Earth masses can slide along slopes at a barely noticeable speed (such displacements are called slow). In other cases, the rate of displacement of weathering products turns out to be higher (for example, meters per day), sometimes large volumes of rocks collapse at a rate exceeding the speed of the express. All these are slope displacements - landslides. They differ not only in the rate of displacement, but also in the scale of the phenomenon.

The consequences of landslides.

Landslides can destroy homes and endanger entire communities. They threaten agricultural land, destroy it and make it difficult to cultivate it, pose a threat to the exploitation of quarries and the extraction of minerals. Landslides damage communications, tunnels, pipelines, telephone and electrical networks; threaten water facilities, mainly dams. In addition, they can block the valley, form temporary lakes and contribute to floods, as well as generate disastrous waves in lakes and bays, and underwater landslides tear telephone cables. As a result of landslides, river beds, roads can overlap, and the landscape changes. Landslides threaten the safety of road and rail transport. Destroy and damage bridge supports, rails, road surfaces, oil pipelines, hydroelectric power plants, mines and other industrial enterprises, mountain villages. The arable land below the landslide areas is often waterlogged. At the same time, there is a loss of yield and an intensive process of land retirement from agricultural use.

These phenomena can significantly damage the cultural and historical heritage of peoples, the state of mind of people inhabiting mountainous areas.

Landslides mainly occur in areas of living tectonics, where the processes of slow sliding of blocks of the earth's crust along faults and fast movements in the foci of earthquakes interact and alternate.

Landslides on the territory of the Russian Federation take place in the mountainous regions of the North Caucasus, the Urals, Eastern Siberia, Primorye, about. Sakhalin, Kuril Islands, Kola Peninsula, as well as on the banks of large rivers.

Landslides often lead to large-scale disasters For example, the landslide of 1963 in Italy with a volume of 240 million cubic meters. meters covered 5 cities, while killing 3 thousand people. In 1989, landslides in Checheno-Ingushetia caused damage in 82 settlements of 2,518 houses, 44 schools, 4 kindergartens, 60 health care, culture and consumer services.

Occurrence and classification of landslides.

1. Natural causes of landslides.

Landslides can be caused by various factors. Earth surface the whole consists mainly of slopes. Some of them are stable, others, due to different conditions become unstable. This happens when the slope angle changes or if the slope is burdened with loose materials. Thus, the force of gravity is greater than the force of cohesion of the soil. The slope becomes unstable even with tremors. Therefore, each earthquake in mountainous terrain is accompanied by displacements along the slope. The instability of the slope is also facilitated by an increase in watering of soils, loose sediments or rocks. Water fills the pores and breaks the adhesion between soil particles. Interstitial water can act like a lubricant and facilitate sliding. The connectivity of rocks can be disrupted during freezing and in the processes of weathering, leaching, and leaching. The instability of the slopes can also be associated with a change in the type of plantations or the destruction of vegetation cover.

The matter is also serious when the rocky rocks on the slope are covered with loose materials or soil. Loose deposits are easily separated from the underlying rocks,

especially if the sliding plane is "smeared with water".

Unfavorable (from the point of view of the possibility of
landslides) and those cases when rocks are presented
layers of hard limestone or sandstone with

underlying softer shales. As a result of weathering, a dividing plane is formed, and the strata slide down the slope. In this case, everything depends mainly on the orientation of the layers. When the direction of their fall and the slope are parallel to the slope, it is always dangerous. It is impossible to accurately determine the value of the slope angle, more than which the slope is unstable, and less than which is stable. Sometimes this critical angle is defined as 25 degrees. The steeper slopes appear to be already unstable, and landslides are most influenced by rainfall and tremors. Landslides always occur during strong earthquakes. Also, the occurrence of landslides is influenced by: the intersection of rocks by cracks, the location of soil layers with an inclination towards the slope, the alternation of waterproof and aquifers, the presence of softened clays and floating sands in the soil, an increase in the steepness of the slope, as a result of erosion (on river banks).

2. Anthropogenic causes the occurrence of landslides.

Landslides can be caused by deforestation and shrubbery on slopes, plowing slopes, over-irrigating slopes, clogging, blockages, and flooding of exit points. groundwater.

The occurrence of landslides is influenced by the production of blasting operations, as a result of which the formation of cracks occurs, and this is also an artificial earthquake.

Landslides can form when slopes are destroyed by foundation pits, trenches and road cuts. Such landslides can occur during the construction of housing and other facilities on the slopes.

Landslide classification.

1. By material

1. 
   rocks
   B) soil layer
2. 
   mixed landslides

2. According to the displacement rate, all slope processes
are subdivided into:

1. 
   extremely fast (3m / s)
   B) very fast (Zdm / m)
2. 
   fast (1.5 meters per day)
   D) moderate (1.5 m per month)

E) very slow (1.5 m per year) E) extremely slow (6 cm per year) Slow offsets(very slow).

They are not catastrophic. They are called dragging, creeping displacement of loose deposits, as well as sliding and slipping. It really is a movement - a creep, because its speed does not exceed several tens of centimeters per year. Such displacement can be recognized by the curved trunks of trees growing on the slope, the bending of the seams and the surface, the so-called stripping, and with the help of sensitive instruments.

Solifluction and gelifluction are types of such slow displacements. Previously, solifluction was understood as displacement in soils and loose sediments saturated with water. Later, this term was extended to glacial conditions, where soils are displaced due to the alternation of freezing and thawing. Currently, it is recommended to use the term "gelifluction" to denote displacements caused by alternating freezing and thawing. The danger of these slow displacements is that they can gradually turn into rapid and then catastrophic displacement. Many large landslides began with loose material slumping or the slow sliding of rock blocks. Bias average speed(fast).

Displacements that occur at a rate of meters per hour or meters per day. These include most of the typical landslides. The landslide area consists of a separation zone, a slip zone and a frontal zone. In the separation zone, the main separation crack and the slip plane along which the landslide body separated from the underlying rock can be distinguished.

Fast offsets.

Only rapid landslides can cause real disasters with hundreds of human casualties. Such displacements include those whose speed is several tens of kilometers per hour (or much more), when escape is impossible (there is no time for a real evacuation).

Known different types such disasters: "Rock collapse". Landslides - flows occur when solid material

mixes with water and flows at high speed. Landslides - streams can be mud (they include volcanic mud streams), stone or transitional. Avalanches, both snow and snow-stone, also belong to fast displacements.

3. By the scale, landslides are subdivided:

A) large

B) medium

C) small-scale.

Large landslides are usually caused by natural causes and form along the slopes for hundreds of meters. Their thickness reaches 10 -20 meters and more. The landslide body often retains its solidity.

Medium and small-scale landslides are smaller and are characteristic of anthropogenic processes.

4. The scale of landslides is characterized by the involvement in the process
area:

1. 
   grandiose -400 hectares and more
   B) very large - 200-400 hectares
2. 
   large - 100-200 ha
   D) medium - 50-100 hectares
   D) small 5-50 hectares

E) very small up to 5 hectares

5. By volume ( power)

A) small (10 thousand cubic meters)

B) medium (from 10 to 100 thousand cubic meters)

B) large (from 100 thousand to 1 million cubic meters)
D) very large (more than 1 million cubic meters)

6. By activity, landslides can be:

A) active

B) not active

Their activity is determined by the degree of capture of the bedrock of the slopes and the speed of movement, which can range from 0.06 m / year to 3 m / s

7. Depending on the availability of water:
A) dry

B) slightly wet

B) very wet

8. By the mechanism of the landslide process:
A) Shear landslides

B) extrusion

B) viscoplastic

D) hydrodynamic

D) sudden liquefaction

Landslides often show signs of a combined mechanism.

9. According to the place of formation, landslides are subdivided:

A) mountain

B) coastal

C) underwater, (B, C,) can cause tsunamis

D) snowy

E) landslides of artificial earth structures (canals,

pits ...)

The magnitude of the consequences is determined by:

1. 
   the size of the population trapped in the landslide zone
2. 
   the number of dead, injured, homeless
3. 
   the number of settlements caught in the zone of natural
   disasters
4. 
   the number of objects of the national economy, medical
   health and social and cultural institutions,
   found destroyed and damaged

5) the area of ​​flooding and heaping of agricultural
land

6) the number of dead farm animals.

Landslide protection measures.

The population living in landslide-prone zones should know the foci, possible directions and characteristics of this dangerous phenomenon. Based on the forecast data, residents are informed in advance about the danger and measures regarding the identified landslide foci and possible zones of their action, as well as the procedure for signaling the threat of this dangerous phenomenon. Also, earlier informing people reduces the impact of stress and panic, which may subsequently arise when transmitting emergency information about an imminent threat of a landslide.

The population of hazardous areas is also obliged to carry out measures to strengthen houses and territories on which they are built, as well as to participate in the construction of protective hydraulic engineering and other engineering structures. The population is alerted using sirens, radio, television, and local warning systems.

In case of a landslide threat and if time is available, an early evacuation of the population, farm animals and property to safe areas is organized. Valuable property that cannot be taken with you should be protected from moisture and dirt. Doors and windows, ventilation and other openings are tightly closed. Electricity, gas, plumbing are cut off. Flammable, poisonous, etc. hazardous substances removed from the house and, as soon as possible, are buried in pits or cellars. In all other respects, citizens act in accordance with the procedure established for organized evacuation.

When there is a threat of a natural disaster, residents, taking care of the property, make an emergency independent exit to a safe place. At the same time, neighbors, all people on the way should be warned about the danger. For an emergency exit, it is necessary to know the routes of movement to the nearest safe places (mountain slopes, hills, not prone to landslide process).

In the case when people, buildings and other structures find themselves on the surface of a moving landslide area, after leaving the room, move upward as much as possible, acting according to the situation, beware when braking the landslide of blocks, stones, debris, structures, earthen wall rolling down from its rear part , talus.

After the end of the landslide, people who hastily left the disaster zone and waited for it in a nearby safe place should, after making sure that there is no repeated threat, return to this zone in order to search for and provide assistance to the injured.

Landslide observation and forecasting.

1. 
   Monitor unusual incidents, behavior
   animals, for precipitation.
2. 
   Analysis and forecasting of possible landslides.

For more accurate forecast necessary:

A) rock mass analysis

B) analysis of the conditions of already known and existing landslides.

B) experience and special knowledge.

3. Carrying out complex protective engineering works.
They are active measures of protection against landslides.

1) Planning slopes, leveling bumps, filling cracks

1. 
   Implementation of planned and strictly metered explosions
2. 
   Construction of tunnels and sheltered fences, as well as protective walls
3. 
   Reducing slope steepness using technique or directional blasting
4. 
   Construction of roads, flyovers, viaducts
5. 
   Construction of retaining walls, construction of rows of piles
6. 
   The device of the guiding walls
7. 
   Interception of groundwater by the drainage system (system of special pipes), regulation of surface runoff with patches and ditches
8. 
   Protection of slopes by sowing grasses, trees and shrubs
9. 
   Relocation of power lines, oil and gas pipelines and
   other objects in safe areas
10. 
    Protection of slopes, road, road and railroad embankments by concreting and landscaping.

1. 
   Education for people living, working and resting in hazardous areas
2. 
   Compliance with the safe mode, building codes and regulations, as well as instructions and standards.

Glacier collapses.

The tongues of mountain glaciers descend into the valleys, where sometimes they even come directly to settlements... In many alpine valleys of the glacier, you can, as they say, touch with your hand. Usually, the translational movement of glacial tongues occurs at a speed of several meters per year, while they melt and feed with water mountain rivers... However, it happens that for some reason the glacier loses its stability and suddenly moves tens or even hundreds of meters in a few days. By itself, this phenomenon does not yet represent a catastrophe, however, the situation is worse when, having lost its stability, the glacier breaks off and falls into the valley.

it stormy streams with mud and boulders. The main component of this mixture is water, it is it that determines the movement of the entire mass. The immediate causes of the onset of mudflows are heavy rainfall, washing of water bodies, intensive melting of snow and ice, earthquakes and volcanic eruptions, deforestation, rock explosions during road construction, improper organization of dumps.

They sat down either fine particles hard material or rough debris. In accordance with this, there are stone streams, mud - stone and mud streams.

Snow avalanches.

Avalanches are also referred to as landslides. Large avalanches are disasters that claim dozens of lives. Every year, several people die under avalanches in our mountains; on the scale of Europe and the whole world, the number of victims of avalanches is much higher.

From the point of view of mechanics, an avalanche occurs in the same way as other landslide displacements. The forces of snow displacement cross a certain boundary, and gravity causes the snow masses to shift along the slope. An avalanche is a mixture of snow and air crystals. Snow quickly after falling out changes its properties, that is, it undergoes metamorphism. Snow crystals grow, the porosity of the snow mass decreases. At a certain depth below the surface, recrystallization can lead to the formation of a sliding surface over which the snow layer will slide. The force of gravity determines the occurrence of tensile forces at the top of the slope. Disturbances in the snow layer in these places usually lead to an avalanche.

The critical angle in this case is 22 degrees. However, this does not mean that an avalanche cannot occur on less steep slopes. Large avalanches occur on the slopes of 25-60 degrees. Their occurrence depends not only on the absolute slope, but also on the profile of the slope. Concave slopes are less avalanche hazard than convex slopes. The bulge of the slope increases the stretching directions, although in winter it is not visible what is hidden under the snow, however, the so-called micro-relief largely determines the possibility of avalanches. Smooth grassy slopes are avalanche-prone. Shrubs, large rocks and other obstacles of this nature keep avalanches from occurring. In the forest, avalanches are very rare, but single trees on the slope do not prevent avalanches. The importance of has a slope orientation: there are fewer avalanches on the southern slopes at the beginning of winter, but at the end of winter, the southern slopes become avalanche-prone, because as a result of melting, the snow cover loses its stability.

There are two main types of avalanches: dust and formation avalanches.

Dust avalanches are formed by a shapeless mixture of snow dust. There is no sliding plane between the shifting snow and the underlying snow. More and more snow is added from below, and the avalanche grows. These avalanches often occur in one place or in a limited area. The formation avalanches are separated by a sliding plane from the base. They arise, like landslides, along the separation zone and slide in the form of a layer, both along the underlying older layers of snow, and along the bedrock slope. Reservoir avalanches are more dangerous than dust ones.

According to their shape, avalanches are also divided into two types: trough avalanches, rolling down hollows and gorges, and flat wasps, moving along a flat surface.

The avalanche speed varies widely. Dust avalanches are faster. Those with a lot of air can reach speeds of up to 120-130 km / h. Heavy dust avalanches move at a speed of 50-70 km / h. Formation avalanches are slower, their speed is 25-36 km / h.

In terms of size, avalanches are divided into large, medium, and small. The big ones destroy everything in their path. Mediums are dangerous only for people, small ones are practically not dangerous.

There are several indirect causes of avalanches: slope instability, snow recrystallization, formation of a slip plane, snow deposits with a larger slope angle than the slope. Concussion is often the direct cause. And a stone falling on a snowy field can cause an avalanche. Avalanches capture in their movement people who cross the snow massif, prepared for separation. A lot of controversy raises the question of whether the avalanche can be caused by sound. Most are doubtful on this score.

Avalanche protection.

As with other landslide displacements, preventive measures are essential. Avalanche elephants are easy to recognize. Studies of previous avalanches are important, as most of them descend on the same slopes, although exceptions are possible.

For avalanche forecasting, both the wind direction and the amount of precipitation are important. When 25 mm of fresh snow falls, the occurrence of avalanches is possible, at 55 mm they are very likely, and at 100 mm one has to admit the possibility of their occurrence

In a few hours. The probability of avalanches is calculated by the rate of melting of the snow field.

Avalanche protection can be passive or active.

At passive protection avoid avalanche slopes or set up protective shields.

Active protection consists in shelling avalanche slopes. Thus, they cause the descent of small, harmless avalanches and prevent the accumulation of critical masses of snow.

Snow avalanches cause great damage and loss of life. So, on July 13, 1990, at Lenin Peak in the Pamirs, as a result of an earthquake, a large snow avalanche demolished the camp of climbers located at an altitude of 5300 m. 48 people died.

Bibliography.

Zdenek Kukal "Natural Disasters" Ed. 23nanie "Moscow 1985

Encyclopedia of Security, V.G. Ponamarev

Ed. 2Stalker "1997

E.P. Emelyanova "Basic laws of landslide processes"

Ed. "Nedra" Moscow 1972