30 dangerous natural phenomena. Dangerous natural phenomena in Russia

Natural emergencies, depending on the type, scale and consequences, are conventionally divided into natural disasters (large in scale and with severe consequences) and natural hazards.

Recently, more and more dangerous phenomena lead to serious consequences and are regarded as emergencies. For example, frost and icing at the beginning of the last century did not cause serious harm, while in the winter of 2001 several regions of Ukraine were left without electricity, which, of course, caused enormous material and economic damage.

Natural disasters- these are dangerous processes of lithospheric, atmospheric, hydrological, biosphere or other origin of such a scale that lead to catastrophic situations with sudden disruptions in the life systems of the population, destruction and destruction of material assets and national economic facilities

Types of natural disasters:

- Meteorological:

o significant increase or decrease in temperature.

- Tectonic:

o earthquake,

o volcanic eruption,

- Topological:

o flood,

o mudflow,

o rockfall,

o snow drifts,

- Space:

o increased radioactive radiation,

o the fall of a large cosmic body.

- Biological:

o abnormal increase in the number of macrobiological objects,

o diseases and damage to plants and animals,

o epidemic.

Hazardous natural phenomena - These are processes that can lead to negative consequences in a small area and become causes of emergencies of natural or man-made origin.

Types of hazardous natural phenomena:

o lightning strike,

o black ice

o strong wind.

Global natural, and in some cases man-made, emergency situations, the environmental consequences of which extend to the entire or most of the planet, are called disasters.

The consequences of some of the largest natural disasters that occurred on Earth are shown in Table 2.2.

Table 2.2

Major natural disasters and the number of their victims

All natural hazards are characterized general principles:

Each type of hazard is preceded by some specific signs;

Despite the unexpected nature of a natural hazard, its occurrence can be foreseen;

The greater the intensity of a dangerous phenomenon, the less often it occurs;

Each type of hazard is characterized by a certain spatial conditionality;

To prevent natural emergencies, passive and active protective measures can be used. Active protection from natural hazards involves the construction of engineering structures, intervention in the mechanism of the phenomenon, reconstruction of natural objects, etc., passive - the use of protective structures. In most cases, passive and active protection methods are combined.

| Materials for life safety lessons for grade 7 | Lesson plan for the academic year | Natural emergencies

Basics of life safety
7th grade

Lesson 1
Natural emergencies

There are concepts "hazardous natural phenomenon" And "disaster".

Dangerous natural phenomenon - this is an event of natural origin or the result of natural processes, which, due to their intensity, scale of distribution and duration, can have a damaging effect on people, economic objects and the environment.

TO natural hazards include earthquakes, volcanic eruptions, floods, tsunamis, hurricanes, storms, tornadoes, landslides, mudflows, forest fires, sudden thaws, cold snaps, warm winters, severe thunderstorms, droughts, etc. But not all, but only those that negatively impact people's livelihoods, the economy and the environment.

Such phenomena cannot include, for example, an earthquake in a desert area where no one lives, or a powerful landslide in an uninhabited mountainous area. They also do not include phenomena that occur in places where people live, but do not cause a sharp change in their living conditions, do not lead to death or injury to people, destruction of buildings, communications, etc.

Disaster - is a destructive natural and (or) natural-anthropogenic phenomenon or process of significant scale, as a result of which a threat to the life and health of people may arise or has arisen, destruction or destruction of material assets and components of the natural environment may occur.

They arise under the influence of atmospheric phenomena (hurricanes, heavy snowfalls, torrential rains), fire (forest and peat fires), changes in water levels in reservoirs (floods, floods), processes occurring in the soil and the earth's crust (volcanic eruptions, earthquakes, landslides , mudflows, landslides, tsunamis).

Approximate ratio of the frequency of occurrence of hazardous natural phenomena by their types.

Natural disasters are usually natural emergencies. They can occur independently of each other, and sometimes one natural disaster leads to another. As a result of earthquakes, for example, avalanches or landslides can occur. And some natural disasters occur due to human activity, sometimes unreasonable (a cigarette butt thrown unextinguished or an unextinguished fire, for example, often leads to a forest fire, explosions in mountainous areas during road construction lead to landslides, landslides, avalanches).

So, the occurrence of a natural emergency is a consequence of a natural phenomenon in which there is a direct threat to the life and health of people, material values ​​and the natural environment are destroyed and destroyed.

Typification of natural phenomena by degree of danger

Such phenomena can have different origins, which became the basis for the classification of natural emergencies shown in Diagram 1.

Each natural disaster has its own impact on a person and his health. People suffer the most from floods, hurricanes, earthquakes and droughts. And only about 10% of the damage it causes comes from other natural disasters.

The territory of Russia is exposed to a wide variety of natural hazards. At the same time, there are significant differences in their manifestation here compared to other countries. Thus, the historically established zone of the main distribution of the population of Russia (from the European part in the south of Siberia to the Far East) approximately coincides with the zone of the least manifestation of such natural hazards as earthquakes, hurricanes and tsunamis (except for the Far East). At the same time, the high prevalence of unfavorable and dangerous natural processes and phenomena is associated with cold, snowy winters. In general, the damage caused by natural emergencies in Russia is below the global average due to a significantly lower population density and the location of hazardous industries, as well as as a result of the adoption of preventive measures.

Grishin Denis

Natural disasters have threatened the inhabitants of our planet since the beginning of civilization. Somewhere more, somewhere less. One hundred percent security does not exist anywhere. Natural disasters can cause enormous damage. In recent years, the number of earthquakes, floods, landslides and other natural disasters has been constantly increasing. In my essay I want to consider dangerous natural processes in Russia.

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ADMINISTRATION OF THE CITY OF NIZHNY NOVGOROD

Municipal budgetary educational institution

Secondary school No. 148

Students' Scientific Society

Natural hazards in Russia

Completed by: Grishin Denis,

6a grade student

Supervisor:

Sinyagina Marina Evgenievna,

geography teacher

Nizhny Novgorod

27.12.2011

PLAN

Page

Introduction

Chapter 1. Natural hazards (natural emergencies).

1.1. The concept of emergency situations.

1.2. Natural disasters of a geographical nature.

1.3. Natural disasters of a meteorological nature.

1.4. Natural disasters of a hydrological nature.

1.5. Natural fires.

Chapter 2. Natural disasters in the Nizhny Novgorod region.

Chapter 3. Measures to combat natural disasters.

Conclusion

Literature

Applications

Introduction

In my essay I want to consider dangerous natural processes.

Natural disasters have threatened the inhabitants of our planet since the beginning of civilization. Somewhere more, somewhere less. One hundred percent security does not exist anywhere. Natural disasters can cause enormous damage.

Natural emergencies (natural disasters) have been on the rise in recent years. The activities of volcanoes are intensifying (Kamchatka), earthquakes are becoming more frequent (Kamchatka, Sakhalin, Kuril Islands, Transbaikalia, North Caucasus), and their destructive power is increasing. Floods have become almost regular (the Far East, the Caspian lowland, the Southern Urals, Siberia), and landslides along rivers and in mountainous areas are not uncommon. Ice, snow drifts, storms, hurricanes and tornadoes visit Russia every year.

Unfortunately, in areas of periodic flooding, the construction of multi-storey buildings continues, which increases the concentration of the population, underground communications are laid, and dangerous industries operate. All this leads to the fact that the usualFloods in these places are causing more and more catastrophic consequences.

In recent years, the number of earthquakes, floods, landslides and other natural disasters has been constantly increasing.

The purpose of my essay is to study natural emergencies.

The purpose of my work is to study hazardous natural processes (natural emergencies) and measures to protect against natural disasters.

1. Concept of natural emergencies

1.1.Natural emergencies –the situation in a certain territory or water area as a result of the occurrence of a source of natural emergencies that can or will result in human casualties, damage to human health or the natural environment, significant losses and disruption of people’s living conditions.

Natural emergencies are distinguished by the nature of their source and scale.

Natural emergencies themselves are very diverse. Therefore, based on the reasons (conditions) of their occurrence, they are divided into groups:

1) dangerous geophysical phenomena;

2) dangerous geological phenomena;

3) dangerous meteorological phenomena;

4) marine hazardous hydrometeorological phenomena;

5) dangerous hydrological phenomena;

6) natural fires.

Below I want to take a closer look at these types of natural emergencies.

1.2. Natural disasters of a geophysical nature

Natural disasters associated with geological natural phenomena are divided into disasters caused by earthquakes and volcanic eruptions.

EARTHQUAKES - These are tremors and vibrations of the earth's surface, caused mainly by geophysical reasons.

Complex processes are constantly taking place in the bowels of the earth. Under the influence of deep tectonic forces, stress arises, layers of earth rocks are deformed, compressed into folds and, with the onset of critical overloads, they shift and tear, forming faults in the earth's crust. The rupture is accomplished by an instantaneous shock or a series of shocks that have the nature of a blow. During an earthquake, the energy accumulated in the depths is discharged. The energy released at depth is transmitted through elastic waves in the thickness of the earth's crust and reaches the surface of the Earth, where destruction occurs.

There are two main seismic belts: the Mediterranean-Asian and the Pacific.

The main parameters characterizing an earthquake are their intensity and focal depth. The intensity of an earthquake on the Earth's surface is assessed in points (see. Table 1 in the Appendices).

Earthquakes are also classified by the reason they occur. They can arise as a result of tectonic and volcanic manifestations, landslides (rockbursts, landslides) and, finally, as a result of human activity (filling reservoirs, pumping water into wells).

Of considerable interest is the classification of earthquakes not only by severity, but also by number (recurrence frequency) during the year on our planet.

Volcanic activity

arises as a result of constant active processes occurring in the depths of the Earth. After all, the inside is constantly in a heated state. During tectonic processes, cracks form in the earth's crust. Magma rushes along them to the surface. The process is accompanied by the release of water vapor and gases, which create enormous pressure, eliminating obstacles in its path. When reaching the surface, part of the magma turns into slag, and the other part flows out in the form of lava. From the vapors and gases released into the atmosphere, volcanic rocks called tephra precipitate onto the ground.

According to the degree of activity, volcanoes are classified into active, dormant and extinct. Active ones include those that erupted in historical times. Extinct ones, on the contrary, did not erupt. Dormant ones are characterized by the fact that they periodically manifest themselves, but it does not come to the point of eruption.

The most dangerous phenomena that accompany volcanic eruptions are lava flows, tephra fallout, volcanic mud flows, volcanic floods, scorching volcanic clouds and volcanic gases.

Lava flows - these are molten rocks with a temperature of 900 - 1000 °. The flow speed depends on the slope of the volcano cone, the degree of viscosity of the lava and its quantity. The speed range is quite wide: from a few centimeters to several kilometers per hour. In some and the most dangerous cases it reaches 100 km, but most often it does not exceed 1 km/h.

Tephra consists of fragments of solidified lava. The largest ones are called volcanic bombs, the smaller ones are called volcanic sand, and the smallest ones are called ash.

Mud flows - these are thick layers of ash on the slopes of the volcano, which are in an unstable position. When new portions of ash fall on them, they slide down the slope

Volcanic floods. When glaciers melt during eruptions, huge amounts of water can form very quickly, which leads to floods.

A scorching volcanic cloud is a mixture of hot gases and tephra. Its damaging effect is caused by the appearance of a shock wave (strong wind), spreading at a speed of up to 40 km/h, and a wave of heat with a temperature of up to 1000°.

Volcanic gases. An eruption is always accompanied by the release of gases mixed with water vapor - a mixture of sulfur and sulfur oxides, hydrogen sulfide, hydrochloric and hydrofluoric acids in a gaseous state, as well as carbon dioxide and carbon monoxide in high concentrations, which are deadly to humans.

Classification of volcanoesis carried out according to the conditions of their occurrence and the nature of the activity. According to the first sign, four types are distinguished.

1) Volcanoes in subduction zones or zones of subduction of the oceanic plate under the continental plate. Due to thermal concentration in the depths.

2) Volcanoes in rift zones. They arise due to weakening of the Earth's crust and bulging of the boundary between the Earth's crust and mantle. The formation of volcanoes here is associated with tectonic phenomena.

3) Volcanoes in zones of large faults. In many places in the earth's crust there are ruptures (faults). There is a slow accumulation of tectonic forces that can turn into a sudden seismic explosion with volcanic manifestations.

4) Volcanoes of “hot spot” zones. In certain areas under the ocean floor, “hot spots” are formed in the earth’s crust, where particularly high thermal energy is concentrated. In these places, rocks melt and come to the surface in the form of basaltic lava.

According to the nature of activity, volcanoes are divided into five types (see. Table 2)

1.3. Natural disasters of a geological nature

Natural disasters of a geological nature include landslides, mudflows, avalanches, landslides, and subsidence of the earth's surface as a result of karst phenomena.

Landslides is a sliding displacement of rock masses down a slope under the influence of gravity. They are formed in various rocks as a result of an imbalance or weakening of their strength. Caused by both natural and artificial (anthropogenic) reasons. Natural ones include: increasing the steepness of slopes, eroding their bases with sea and river waters, seismic tremors. Artificial causes include the destruction of slopes by road cuttings, excessive removal of soil, deforestation, and unwise farming on slopes. According to international statistics, up to 80% of modern landslides are associated with human activity. They occur at any time of the year, but mostly in the spring and summer.

Landslides are classifiedby the scale of the phenomenon, speed of movement and activity, mechanism of the process, power and place of formation.

Based on their scale, landslides are classified into large, medium and small-scale.

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

Medium and small-scale ones are smaller in size and are characteristic of anthropogenic processes.

Scale is often characterized by the area involved. The speed of movement is very varied.

Based on activity, landslides are divided into active and inactive. The main factors here are the rocks of the slopes and the presence of moisture. Depending on the amount of moisture, they are divided into dry, slightly wet, wet and very wet.

According to the mechanism of the process, they are divided into: shear landslides, extrusion landslides, viscoplastic landslides, hydrodynamic landslides, and sudden liquefaction landslides. Often have signs of a combined mechanism.

According to the place of formation, they are divided into mountain, underwater, adjacent and artificial earthen structures (pits, canals, rock dumps).

Mudflow (mudflow)

A rapid mud or mud-stone flow, consisting of a mixture of water and rock fragments, suddenly appearing in the basins of small mountain rivers. It is characterized by a sharp rise in water level, wave movement, short duration of action (on average from one to three hours), and a significant erosion-accumulative destructive effect.

The immediate causes of the formation of gray lakes are rainfall, intense snow melting, outburst of reservoirs, and, less commonly, earthquakes and volcanic eruptions.

All mudflows, according to the mechanism of their origin, are divided into three types: erosion, breakthrough and landslide.

With erosion, the water flow is first saturated with debris due to the washout and erosion of the adjacent soil, and then a mudflow wave is formed.

During a landslide, the mass is torn down to saturated rocks (including snow and ice). The flow saturation in this case is close to maximum.

In recent years, man-made factors have been added to the natural causes of the formation of mudflows: violation of the rules and regulations of mining enterprises, explosions during the construction of roads and the construction of other structures, logging, improper agricultural practices and disturbance of soil and vegetation cover.

When moving, a mudflow is a continuous stream of mud, stones and water. Based on the main factors of occurrence, mudflows are classified as follows;

Zonal manifestation. The main formation factor is climatic conditions (precipitation). They are zonal in nature. The convergence occurs systematically. The paths of movement are relatively constant;

Regional manifestation. The main formation factor is geological processes. The descent occurs sporadically, and the paths of movement are not constant;

Anthropogenic. This is the result of human economic activity. Occur where there is the greatest load on the mountain landscape. New mudflow basins are formed. The gathering is episodic.

Snow avalanches - snow masses falling from mountain slopes under the influence of gravity.

Snow accumulating on mountain slopes, under the influence of gravity and weakening of structural bonds within the snow column, slides or crumbles down the slope. Having started its movement, it quickly picks up speed, capturing more and more snow masses, stones and other objects along the way. The movement continues to flatter areas or the bottom of the valley, where it slows down and stops.

Avalanches form within the avalanche source. An avalanche source is a section of a slope and its foot within which an avalanche moves. Each source consists of 3 zones: origin (avalanche collection), transit (trough), and stopping of the avalanche (alluvial cone).

Avalanche-forming factors include: the height of old snow, the condition of the underlying surface, the increase in freshly fallen snow, snow density, snowfall intensity, subsidence of snow cover, snowstorm redistribution of snow cover, air and snow cover temperatures.

The ejection range is important for assessing the possibility of hitting objects located in avalanche zones. A distinction is made between the maximum emission range and the most probable, or long-term average. The most probable ejection range is determined directly on the ground. It is assessed if it is necessary to place structures in the avalanche zone for a long period. It coincides with the boundary of the avalanche fan.

The frequency of avalanches is an important temporal characteristic of avalanche activity. A distinction is made between average long-term and intra-annual recurrence rates. The density of avalanche snow is one of the most important physical parameters, which determines the impact force of the snow mass, the labor costs for clearing it, or the ability to move on it.

How are they classified?

According to the nature of the movement and depending on the structure of the avalanche source, the following three types are distinguished: flume (moves along a specific drainage channel or avalanche chute), wasp (snow landslide, does not have a specific drainage channel and slides across the entire width of the area), jumping (arising from flume where the drainage channel has steep walls or areas with sharply increasing steepness).

According to the degree of repeatability, they are divided into two classes - systematic and sporadic. Systematic ones go every year or once every 2-3 years. Sporadic - 1-2 times per 100 years. It is quite difficult to determine their location in advance.

1.4. Natural disasters of a meteorological nature

All of them are divided into disasters caused by:

by the wind, including a storm, hurricane, tornado (at a speed of 25 m/s or more, for the Arctic and Far Eastern seas - 30 m/s or more);

Heavy rain (with precipitation of 50 mm or more in 12 hours or less, and in mountainous, mudflow and storm-prone areas - 30 mm or more in 12 hours or less);

Large hail (for hailstones with a diameter of 20 mm or more);

Heavy snowfall (with precipitation of 20 mm or more in 12 hours or less);

- strong snowstorms(wind speed 15 m/s or more);

Dust storms;

frosts (when the air temperature drops during the growing season on the soil surface below 0°C);

- severe frost or extreme heat.

These natural phenomena, in addition to tornadoes, hail and squalls, lead to natural disasters, as a rule, in three cases: when they occur in one third of the territory of the region (region, republic), cover several administrative districts and last for at least 6 hours.

Hurricanes and storms

In the narrow sense of the word, a hurricane is defined as a wind of great destructive force and significant duration, the speed of which is approximately 32 m/s or more (12 points on the Beaufort scale).

A storm is a wind whose speed is less than the speed of a hurricane. Losses and destruction from storms are significantly less than from hurricanes. Sometimes a strong storm is called a storm.

The most important characteristic of a hurricane is wind speed.

The average duration of a hurricane is 9 - 12 days.

A storm is characterized by a wind speed lower than that of a hurricane (15 -31 m/s). Duration of storms- from several hours to several days, width - from tens to several hundred kilometers. Both are often accompanied by fairly significant precipitation.

Hurricanes and stormy winds in winter often lead to snow storms, when huge masses of snow move from one place to another at high speed. Their duration can be from several hours to several days. Snowstorms that occur simultaneously with snowfall, at low temperatures or with sudden changes in temperature are especially dangerous.

Classification of hurricanes and storms.Hurricanes are usually divided into tropical and extratropical. In addition, tropical hurricanes are often divided into hurricanes that originate over the Atlantic Ocean and over the Pacific Ocean. The latter are usually called typhoons.

There is no generally accepted, established classification of storms. Most often they are divided into two groups: vortex and flow. Vortex formations are complex vortex formations caused by cyclonic activity and spreading over large areas. Streams are local phenomena of small distribution.

Vortex storms are divided into dust, snow and squall. In winter they turn into snow. In Russia, such storms are often called blizzards, blizzards, and blizzards.

Tornado is an ascending vortex consisting of extremely rapidly rotating air mixed with particles of moisture, sand, dust and other suspended matter. It is a rapidly rotating air funnel hanging from a cloud and falling to the ground in the form of a trunk.

They occur both over the water surface and over land. Most often - during hot weather and high humidity, when air instability in the lower layers of the atmosphere appears especially sharply.

A funnel is the main component of a tornado. It is a spiral vortex. Its internal cavity is from tens to hundreds of meters in diameter.

It is extremely difficult to predict the location and time of a tornado.Classification of tornadoes.

Most often they are divided according to their structure: dense (sharply limited) and vague (vaguely limited). In addition, tornadoes are divided into 4 groups: dust devils, small short-acting ones, small long-acting ones, hurricane whirlwinds.

Small short-acting tornadoes have a path length of no more than a kilometer, but have significant destructive power. They are relatively rare. The path length of small long-acting tornadoes is several kilometers. Hurricane vortices are larger tornadoes and travel several tens of kilometers during their movement.

Dust (sand) stormsaccompanied by the transfer of large quantities of soil and sand particles. They occur in desert, semi-desert and plowed steppes and are capable of transporting millions of tons of dust over hundreds and even thousands of kilometers, covering an area of ​​several hundred thousand square kilometers.

Dustless storms. They are characterized by the absence of dust entrainment into the air and a relatively smaller scale of destruction and damage. However, with further movement they can turn into a dust or snow storm, depending on the composition and condition of the earth's surface and the presence of snow cover.

Blizzards characterized by significant wind speeds, which contributes to the movement of huge masses of snow through the air in winter. Their duration ranges from several hours to several days. They have a relatively narrow range (up to several tens of kilometers).

1.5. Natural disasters of a hydrological nature and marine hazardous hydrometeorological phenomena

These natural phenomena are divided into disasters caused by:

High water levels - floods, which cause flooding of low-lying parts of cities and other populated areas, agricultural crops, damage to industrial and transport facilities;

Low water levels, when navigation, water supply to cities and national economic facilities, and irrigation systems are disrupted;

Mudflows (during the breakthrough of dammed and moraine lakes that threaten populated areas, roads and other structures);

Snow avalanches (if there is a threat to populated areas, roads and railways, power lines, industrial and agricultural facilities);

Early freeze-up and the appearance of ice on navigable bodies of water.

Marine hydrological phenomena: tsunamis, strong waves on the seas and oceans, tropical cyclones (typhoons), ice pressure and intense drift.

Floods - is the flooding of water adjacent to a river, lake or reservoir, which causes material damage, damages public health or leads to death. If flooding is not accompanied by damage, it is a flood of a river, lake, or reservoir.

Particularly dangerous floods are observed on rivers fed by rain and glaciers, or by a combination of these two factors.

Flood is a significant and rather prolonged rise in the water level in the river that occurs annually in the same season. Typically, floods are caused by spring melting of snow on the plains or by rainfall.

A flood is an intense, relatively short-term rise in water level. Formed by heavy rains, sometimes by melting snow during winter thaws.

The most important basic characteristics are the maximum level and maximum flow of water during a flood. WITH The maximum level is related to the area, layer and duration of flooding of the area. One of the main characteristics is the rate of rise of the water level.

For large river basins, an important factor is one or another combination of flood waves of individual tributaries.

For cases of flood, the factors influencing the values ​​of the main characteristics include: the amount of precipitation, its intensity, duration, coverage area preceding precipitation, basin moisture, soil permeability, basin topography, river slopes, the presence and depth of permafrost.

Ice jams and jams on rivers

Congestion - This is an accumulation of ice in the riverbed that limits the flow of the river. As a result, water rises and spills.

Jams usually form at the end of winter and in spring when rivers open up during the destruction of the ice cover. It consists of large and small ice floes.

Zazhor - a phenomenon similar to ice jam. However, firstly, a jam consists of an accumulation of loose ice (slush, small pieces of ice), while a jam is an accumulation of large and, to a lesser extent, small ice floes. Secondly, ice jams are observed at the beginning of winter, while ice jams occur at the end of winter and spring.

The main reason for the formation of ice jams is the delay in the opening of ice on those rivers where the edge of the ice cover in the spring moves from top to bottom downstream. In this case, the crushed ice moving from above encounters an undisturbed ice cover on its way. The sequence of river opening from top to bottom downstream is a necessary but not sufficient condition for the occurrence of a jam. The main condition is created only when the surface velocity of the water flow at the opening is quite significant.

Ice jams form on rivers during the formation of ice cover. A necessary condition for formation is the appearance of inland ice in the channel and its involvement under the edge of the ice cover. The surface velocity of the current, as well as the air temperature during the freezing period, are of decisive importance.

Surges is a rise in water level caused by the influence of wind on the water surface. Such phenomena occur at the mouths of large rivers, as well as on large lakes and reservoirs.

The main condition for its occurrence is strong and prolonged wind, which is typical for deep cyclones.

Tsunami - These are long waves resulting from underwater earthquakes, as well as volcanic eruptions or landslides on the seabed.

Their source is at the bottom of the ocean,

In 90% of cases, tsunamis are caused by underwater earthquakes.

Often before a tsunami begins, the water recedes far from the shore, exposing the seabed. Then the approaching one becomes visible. At the same time, thunderous sounds are heard created by the air wave that the water mass carries in front of it.

Possible scales of consequences are classified by points:

1 point - the tsunami is very weak (the wave is recorded only by instruments);

2 points - weak (can flood a flat coast. Only specialists notice it);

3 points - average (noted by everyone. The flat coast is flooded. Light ships may be washed ashore. Port facilities may receive minor damage);

4 points - strong (the coast is flooded. Coastal buildings are damaged. Large sailing and small motor vessels can be washed ashore and then washed back into the sea. Human casualties are possible);

5 points - very strong (coastal areas are flooded. Breakwaters and jetties are severely damaged, Large ships are thrown ashore. There are casualties. There is great material damage).

1.6. Wildfires

This concept includes forest fires, fires of steppe and grain massifs, peat and underground fires of fossil fuels. We will focus only on forest fires, as the most common phenomenon, causing colossal losses and sometimes leading to human casualties.

Forest fires is an uncontrolled burning of vegetation that spontaneously spreads throughout the forest area.

In hot weather, if there is no rain for 15 to 18 days, the forest becomes so dry that any careless handling of fire causes a fire that quickly spreads throughout the forest area. A negligible number of fires occur from lightning discharges and spontaneous combustion of peat crumbs. The possibility of forest fires is determined by the degree of fire danger. For this purpose, a “Scale for assessing forest areas according to the degree of fire danger in them” has been developed (see. Table 3)

Classification of forest fires

Depending on the nature of the fire and the composition of the forest, fires are divided into ground fires, crown fires, and soil fires. Almost all of them at the beginning of their development have a grassroots character and, if certain conditions are created, they turn into upland or soil ones.

The most important characteristics are the speed of spread of ground and crown fires and the depth of underground burning. Therefore, they are divided into weak, medium and strong. Based on the speed of fire spread, ground and top fires are divided into stable and fugitive. The intensity of combustion depends on the condition and supply of combustible materials, the slope of the terrain, the time of day and especially the strength of the wind.

2. Natural emergencies in the Nizhny Novgorod region.

The region's territory has a fairly wide variety of climatic, landscape and geological conditions, which causes the occurrence of various natural phenomena. The most dangerous of them are those that can cause significant material damage and lead to death.

- hazardous meteorological processes:squally and hurricane winds, heavy rain and snow, downpours, large hail, severe snowstorm, severe frost, ice and frost deposits on wires, extreme heat (high fire danger due to weather conditions);agrometeorological,such as frost, drought;

- hazardous hydrological processes,such as floods (in the spring, rivers in the region are characterized by high water levels, coastal ice floes may break off, ice jams are possible), rain floods, low water levels (in summer, autumn and winter, water levels are likely to decrease to unfavorable and dangerous levels);hydrometeorological(separation of coastal ice floes with people);

- natural fires(forest, peat, steppe and fires in wetlands);

- hazardous geological phenomena and processes:(landslides, karsts, subsidence of loess rocks, erosion and abrasion processes, slope washouts).

Over the past thirteen years, of all registered natural phenomena that had a negative impact on the livelihoods of the population and the operation of economic facilities, the share of meteorological (agrometeorological) hazards amounted to 54%, exogenous-geological - 18%, hydrometeorological - 5%, hydrological - 3%, large forest fires - 20%.

The frequency of occurrence and area of ​​distribution of the above natural phenomena in the region are not the same. Actual data from 1998 to 2010 make it possible to classify meteorological phenomena (harmful squally winds, the passage of thunderstorm fronts with hail, ice and frost deposits on wires) as the most common and frequently observed - an average of 10 - 12 cases are recorded annually.

At the end of winter and spring of each year, events are carried out to rescue people from broken coastal ice floes.

Natural fires occur every year and water levels rise during flood periods. Adverse consequences of forest fires and high water levels are recorded quite rarely, which is due to pre-planned preparations for floods and fire hazard periods.

Spring flood

The passage of floods in the region is observed from the end of March to May. In terms of the degree of danger, floods in the region are of the moderately dangerous type, when the maximum levels of water rise are 0.8 - 1.5 m higher than the levels at which flooding begins, flooding of coastal areas (emergency situations at the municipal level). The flood area of ​​the river floodplain is 40 - 60%. Settled areas are usually subject to partial flooding. The frequency of water level exceeding the critical level is every 10 - 20 years. Excesses of critical levels on most rivers in the region were recorded in 1994 and 2005. To one degree or another, 38 districts of the region are exposed to hydrological processes during the spring flood period. The results of the processes are flooding and flooding of residential buildings, livestock and agricultural complexes, destruction of sections of roads, bridges, dams, dams, damage to power lines, and increased landslides. According to recent data, the areas most susceptible to flood phenomena were Arzamas, Bolsheboldinsky, Buturlinsky, Vorotynsky, Gaginsky, Kstovsky, Perevozsky, Pavlovsky, Pochinkovsky, Pilninsky, Semenovsky, Sosnovsky, Urensky and Shatkovsky.

Increased ice thickness can cause congestion on rivers during the break-up period. The number of ice jams on the region's rivers averages 3-4 per year. The flooding (flooding) caused by them is most likely in populated areas located along the banks of rivers flowing from south to north, the opening of which occurs in the direction from the source to the mouth.

Forest fires

In total, there are 304 settlements in the region in 2 urban districts and 39 municipal areas that may be subject to the negative impact of forest-peat fires.

Wildfire hazards involve the occurrence of large wildfires. Fires whose area reaches 50 hectares account for 14% of the total number of large forest fires, fires from 50 to 100 hectares occupy 6% of the total, fires from 100 to 500 hectares - 13%; the share of large forest fires exceeding 500 hectares is small – 3%. This ratio changed significantly in 2010, when the bulk (42%) of large forest fires reached an area of ​​more than 500 hectares.

The number and area of ​​natural fires vary significantly from year to year, because they directly depend on weather conditions and anthropogenic factors (visitation of forests, preparation for the fire season, etc.).

It should be noted that almost throughout the entire territory of Russia in the period up to 2015. One should expect an increase in the number of days with high air temperatures in summer. At the same time, the likelihood of extremely long periods with critical air temperatures will increase significantly. In this regard, by 2015 Compared to current values, an increase in the number of days with fire danger is predicted.

1. MEASURES FOR PROTECTION AGAINST NATURAL DISASTERS.

Over many centuries, humanity has developed a fairly coherent system of measures to protect against natural disasters, the implementation of which in various parts of the world could significantly reduce the number of human casualties and the amount of material damage. But until today, unfortunately, we can only talk about isolated examples of successful resistance to the elements. Nevertheless, it is advisable to once again list the main principles of protection against natural disasters and compensation for their consequences. Clear and timely forecasting of the time, location and intensity of a natural disaster is necessary. This makes it possible to promptly notify the population about the expected impact of the elements. A correctly understood warning allows people to prepare for a dangerous phenomenon by either temporary evacuation, or the construction of protective engineering structures, or strengthening their own homes, livestock premises, etc. The experience of the past must be taken into account, and its hard lessons must be brought to the attention of the population with an explanation that such a disaster can happen again. In some countries, the state buys land in areas of potential natural disasters and organizes subsidized travel from hazardous areas. Insurance is important to reduce losses due to natural disasters.

An important role in preventing damage from natural disasters belongs to the engineering-geographical zoning of potential disaster zones, as well as the development of building codes and regulations that strictly regulate the type and nature of construction.

Various countries have developed fairly flexible legislation on economic activities in disaster zones. If a natural disaster occurs in a populated area and the population was not evacuated in advance, rescue operations are carried out, followed by repair and restoration work.

Conclusion

So I studied natural emergencies.

I have come to realize that there is a wide variety of natural disasters. These are dangerous geophysical phenomena; hazardous geological phenomena; hazardous meteorological phenomena; marine hazardous hydrometeorological phenomena; hazardous hydrological phenomena; natural fires. There are 6 types and 31 species in total.

Natural emergencies can result in loss of life, damage to human health or the environment, significant losses and disruption of people's living conditions.

From the point of view of the possibility of carrying out preventive measures, hazardous natural processes, as a source of emergency situations, can be predicted with very little advance notice.

In recent years, the number of earthquakes, floods, landslides and other natural disasters has been constantly increasing. This cannot go unnoticed.

List of used literature

1. V.Yu. Mikryukov “Ensuring life safety” Moscow - 2000.

2. Hwang T.A., Hwang P.A. Life safety. - Rostov n/d: “Phoenix”, 2003. - 416 p.

3. Reference data on emergencies of man-made, natural and environmental origin: In 3 hours - M.: GO USSR, 1990.

4. Emergency situations: Brief description and classification: Textbook. allowance / Author. benefits A.P. Zaitsev. - 2nd ed., rev. and additional - M.: Journal "Military knowledge", 2000.

A hazardous geological phenomenon is an event that occurs as a result of the activity of geological processes that occur in the earth's crust under the influence of various geological or natural factors or their combination, and have a negative impact on plants, people, animals, the natural environment, and 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 the following:

• screes and landslides;
• sat down;
• subsidence or failure of the earth's surface as a result of karst;
• kurums;
• erosion, abrasion;
• avalanches;
• flushes;
• landslides.

Each type has its own characteristics.

Landslides

Landslides are a geological hazard that is a sliding displacement of rock masses along slopes under the influence of their own weight. This phenomenon occurs as a result of erosion of the slope, due to seismic shocks or under other circumstances.

Landslides occur on the slopes of hills and mountains, and on steep river banks. They can be caused by a variety of natural phenomena:

• earthquakes;
• intense precipitation;
• uncontrolled plowing of slopes;
• cutting slopes when laying roads;
• as a result of deforestation;
• during blasting operations;
• during 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 ground rocks, causing destruction. All loose deposits are saturated with moisture: the resulting layer acts as a lubricant between layers of earthen rocks. When the inner layers rupture, the detached mass begins to float down the slope, as it were.

Landslide classification

There are several types of dangerous geological phenomena, divided by speed of movement:

1. Very fast. They are characterized by mass movement at a speed of 0.3 m/min.
2. Fast ones are characterized by the movement of masses at a speed of 1.5 m/day.
3. Moderate - landslides occur at a speed of up to one and a half meters per month.
4. Slow - movement speed - up to one and a half meters per year.
5. 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 is divided as follows:

• grandiose, occupying an area of ​​more than four hundred hectares;
• very large - landslide area - about two hundred hectares;
• large - area - about a hundred hectares;
• small - 50 hectares;
• very small - less than five hectares.

The thickness of a landslide is characterized by the volume of displaced 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 water level, occurring 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 small diameter stones on the slopes. Secondly, to wash it all off the slope, you need a lot of water. Thirdly, mudflows can only occur on steep slopes, with a slope angle of about twelve degrees.

Causes of mudflows

A dangerous mudflow can occur for various 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.

Mudflows can occur as a result of human activities. An example of this is deforestation on mountain slopes, quarrying or mass construction.

snow avalanche

A snow avalanche is also a dangerous geological natural phenomenon. During an avalanche, a mass of snow slides down the steep slopes of mountains. Its speed can reach one hundred meters per second.

During the fall of an avalanche, a pre-avalanche air wave is formed, causing great damage to the surrounding nature and any objects built in the path of the phenomenon.

Why does an avalanche happen?

There are several reasons why an avalanche begins. These include:

• intensive snow melting;
• long snowfall, which results in a large snow mass that is unable to stay on the slopes;
• earthquakes.

Avalanches can occur due to strong noise. This phenomenon is provoked by air vibrations resulting from sounds emitted at a certain frequency and with a certain strength.

As a result of an avalanche, buildings and engineering structures are destroyed. Any obstacles in its path are destroyed: bridges, power lines, oil pipelines, roads. This phenomenon causes great damage to 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 a lot of snowfall. These are Western and Eastern Siberia, the Far East, the Urals, as well as the North Caucasus and the mountains of the Kola Peninsula.

Avalanches account for approximately half of all mountain accidents. The most dangerous periods of the year are considered to be winter and spring. During these periods, up to 90% of snow melting is recorded. An avalanche can occur at any time of the day, but most often the snow melts 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! As you move, the snow sweeps away everything in its path. If a person falls over, he will not be able to breathe, since the snow clogs the airways, penetrating dust into the lungs. People can freeze, get severe injuries, and frostbite of internal organs.

Collapses

And what other phenomena are classified as geological hazards and what are they? These include collapses. These are detachments of large masses of rocks onto river valleys and sea coasts. Landslides occur due to the separation of masses from the maternal base. Landslides can block or destroy roads and cause huge amounts of water to overflow from reservoirs.

Landslides are small, medium and large. The latter include rock detachments weighing more than ten million cubic meters. Medium debris includes debris with a volume of one hundred thousand to ten million cubic meters. The mass of small landslides reaches tens of cubic meters.

Landslides can occur as a result of the geological structure of the area, as well as cracks on the mountain slopes. The cause of landslides can be human activity. This phenomenon is observed during crushing of rocks, as well as due to a large amount of moisture.

As a rule, collapses occur suddenly. Initially, a crack forms in the rock. Gradually it increases, causing the breed to separate from the parent formation.

Earthquakes

When asked: “Indicate dangerous geological phenomena,” the first thing that comes to mind is earthquakes. This species is considered one of the most terrible, destructive manifestations of nature.

To understand the reasons for this phenomenon, you need to know the structure of the Earth. As is known, it has a solid 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, and overlap each other. Earthquakes occur in the zones of their interaction. However, tremors can occur not only at the edges of the plates, but also in their central part. Other reasons that cause tremors include volcanic eruptions and man-made factors. In some regions, seismic activity is clearly visible due to fluctuations in the water in the reservoir.

The results of earthquakes can be landslides, subsidence, tsunamis, avalanches and much more. One of the dangerous manifestations is soil liquefaction. With this phenomenon, the earth is oversaturated with water, and with tremors 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 the most striking examples of this phenomenon is the liquefaction of soil in 1964 in Japan. The event caused several multi-story buildings to slowly tilt. They didn't have any injuries.

Another manifestation of tremors may be subsidence of the soil. This phenomenon occurs due to particle vibration.

Serious consequences of earthquakes can include ruptures of dams, as well as the occurrence of floods, tsunamis and more.

The main cause of any drought is below average rainfall. Drought differs from other dangerous phenomena in its slow development, which sometimes lasts for several years, and its onset can be hidden by a number of factors. Drought can have devastating consequences: water sources dry up, crops stop growing, animals die, and malnutrition and poor health become widespread.

Tropical cyclones

WMO assists its Members in establishing nationally and regionally coordinated multi-hazard early warning systems that work with national civil protection agencies to minimize loss of life and damage from tropical cyclones. Tropical cyclones are areas of very low atmospheric pressure over tropical and subtropical waters that produce colossal rotating systems of wind and thunderstorms measuring hundreds of kilometers in diameter. They are often associated with extremely heavy rainfall, which can lead to widespread flooding. Cyclones are also associated with destructive winds, and in the most intense systems surface winds can exceed 300 km/h. The combination of wind-driven waves and low pressure in the zone of a tropical cyclone can cause a coastal cyclone - a huge volume of water washed ashore at high speeds and with tremendous force, which can wash away structures in its path and cause significant damage to the coastal environment. In 1970, a massive storm surge caused the death of 300,000 people in a coastal wetland region in Bangladesh, and recent storms such as Typhoon Haiyan (Yolanda) in the Philippines in 2013 have caused large numbers of casualties and widespread destruction. About 80 tropical cyclones form annually. Their names depend on the place where they form: in the western North Pacific Ocean and the South China Sea they are called typhoons; in the Atlantic, Caribbean and Gulf of Mexico, as well as in the eastern northern and central Pacific Ocean - by hurricanes, and in the Indian Ocean and South Pacific region - by tropical cyclones. provides information on these hazards, and the WMO Severe Weather Information Center provides real-time tropical cyclone advisories.

Air pollution

Air pollutants include particles and harmful gases produced by industrial plants, vehicles and human activities. Smoke and haze are the result of forest fires or grass fires, as well as the burning of forest or crop residues, and the formation of volcanic ash due to volcanic eruptions when the atmosphere is stable. Smoke, haze and pollution have serious consequences for human health and local populations may require masks to protect themselves from the gas. As a result of these phenomena, visibility is reduced and disruptions in air and road transport may occur. Other results of air pollution include smog, acid rain, the ozone hole and the adverse increase in the greenhouse effect. Often the stable state of the atmosphere leads to the concentration of pollutants in urban and industrial areas characterized by significant amounts of emissions. The WMO Atmospheric Research and Environment Program manages the Global Atmosphere Watch, which collects observational data on atmospheric pollutants.

Desert Locust

Desert locusts cause damage in Africa, the Middle East, Asia and southern Europe. When weather and environmental conditions are favorable for reproduction, insects concentrate in a small area. They stop acting as individuals and begin acting as a group. After a few months, huge flocks form and move in the direction of the wind in search of food. Swarms can be tens of kilometers long and can travel up to 200 km per day. A small part of an average swarm (or about one ton of locusts) eats in one day the same amount of food as 10 elephants, or 25 camels, or 2,500 people. They pose a threat to the lives of millions of farmers and pastoralists living in vulnerable environments. Locust outbreaks during or immediately after a drought can cause an even worse disaster, as happened in 2005 in several countries in the Sahel region. The WMO-sponsored World Agrometeorological Information Service (WAMIS) website has a Locust Weather page that provides weather information for desert locust monitoring and control.

Floods and flash floods

Floods can occur anywhere after heavy rainfall. All floodplains are vulnerable, and heavy rainfall or thunderstorms can cause flash flooding anywhere in the world. Flash floods can also occur after a period of drought, when moderate to heavy rainfall falls on a very dry and hard surface through which water cannot infiltrate into the ground. Floods come in several types, from small flash floods to sheets of water that cover large areas. They can be caused by severe thunderstorms, tropical cyclones, large low pressure systems, monsoons, ice jams or melting snow. In coastal areas, storm surge caused by a tropical cyclone, tsunami, or rising river levels due to unusually high tides can cause flooding. Flooding can also be caused by exceeding the level of barrier or flood control embankments in the event of floods on rivers caused by snowmelt. In addition, catastrophic flooding can be caused by dam failures or unscheduled water level control operations, such as water releases for hydroelectric power generation. Floods pose a threat to lives and property around the world. In the last decade of the 20th century, nearly 1.5 billion people were affected by floods.

Landslide or mud flow

Mud flows and landslides are local phenomena that, as a rule, occur suddenly. They occur when heavy rainfall, or the rapid melting of snow or ice, or the overflowing of a volcanic lake, erodes weak areas of the landscape on steep slopes, causing large quantities of soil, rocks, sand and dirt to wash down the mountainside. Particularly at risk are hillsides or mountains where vegetation cover is absent or degraded due to logging or forest or brush fires. Such flows can exceed 50 km/h and can completely bury, destroy or carry away people, objects and buildings. In 1999, in Venezuela, after two weeks of continuous rain, landslides and mudflows that came down from the mountain destroyed cities and led to the death of 15 thousand people.

An avalanche is a mass of snow or ice that suddenly descends from the slopes of mountains, often accompanied by soil, rocks and rock debris. Avalanches can cause great destruction, moving at speeds in excess of 150 km/h. The movement of snow creates a strong air wave ahead of it, which can cause serious damage to buildings, forested areas and mountain resorts. Every year thousands of avalanches occur around the world, killing an average of 500 people.

Dust and sand storms

Dust and sandstorms are clouds of dust or sand, sometimes blown to great heights by strong and turbulent winds. They are typical mainly for areas of Africa, Australia, China and the USA. Dust and sand storms pose a threat to life and health, especially if a person is caught in an open area far from shelter. Transport is especially affected, since the visibility zone in some cases is reduced to several meters.

Thermal extremes

Heat waves are most dangerous in mid-latitude regions during the warmer months of the year. They are characterized by significant temperature increases relative to the long-term average during the day and night for several days in a row. Stifling air masses in urban environments can cause increased mortality, especially among the very young, old and frail. During the summer months of 2003, a heat wave swept through almost all of Western Europe. Some 40,000 deaths were reported in Spain, Italy, the Netherlands, Portugal, the United Kingdom and France. Extreme cold also poses a risk, causing hypothermia and exacerbating circulatory and respiratory diseases in people at risk.