These processes and phenomena are associated with various atmospheric processes, and primarily with processes occurring in bottom layer atmosphere - troposphere. In the troposphere there is about 9 /10 of the total mass of air. Influenced solar heat, arriving at the earth's surface, and the forces of gravity in the troposphere are formed clouds, rain, snow, wind.

Air in the troposphere moves in horizontal and vertical directions. Strongly heated air near the equator expands, becomes lighter and rises. There is an upward movement of air. For this reason, a low zone forms at the Earth's surface near the equator. atmospheric pressure. At the poles due to low temperatures the air cools, becomes heavier and sinks. There is a downward movement of air. For this reason, the pressure at the Earth's surface near the poles is high.

In the upper troposphere, on the contrary, above the equator, where ascending air currents predominate, the pressure is high, and above the poles it is low. Air constantly moves from an area of ​​high pressure to an area low blood pressure. Therefore, the air rising above the equator grows towards the poles. But due to the rotation of the Earth around its axis, the moving air does not reach the poles. As it cools, it becomes heavier and sinks at about 30 degrees north and south latitudes, forming areas of high pressure in both hemispheres.

Large volumes of air in the troposphere with homogeneous properties are called air masses. The properties of air masses depend on the territories over which they were formed. As air masses move, they retain their properties for a long time, and when they meet, they interact with each other. The movement of air masses and their interaction determine the weather in those places where these air masses arrive. The interaction of various air masses leads to the formation of moving atmospheric vortices in the troposphere - cyclones and anticyclones.

A cyclone is a flat, rising vortex with low atmospheric pressure at the center. The diameter of a cyclone can be several thousand kilometers. The weather during a cyclone is predominantly cloudy with strong winds.

An anticyclone is a flat downward vortex with high atmospheric pressure with a maximum in the center. In an area of ​​high pressure, the air does not rise, but falls. The air spiral unwinds clockwise in the northern hemisphere. The weather during the anticyclone is partly cloudy, without precipitation, and the wind is weak.

The movement of air masses and their interaction are associated with the emergence of dangerous meteorological phenomena that can cause natural disasters. This iPhones and hurricanes, storms, blizzards, tornadoes, thunderstorms, drought, very coldy and fogs.

Abstract on the topic:

Performed:
1st year student C12 group
Faculty of Social Pedagogy
Volchanskaya Natalya

Taganrog
2011

Content:

Introduction.
Natural disasters.
Hurricanes, storms, tornadoes.

Conclusion.

Introduction.

Natural disasters.

San Angelo, Texas, USA, May 28, 1995: tornadoes and hail hit the city of 90 thousand people; The damage caused is estimated at 120 million US dollars.
Accra, Ghana, July 4, 1995: The heaviest rainfall in nearly 60 years causes severe flooding. About 200,000 residents lost all their property, more than 500,000 more were unable to get into their homes, and 22 people died.

Hurricanes, storms, tornadoes.

during the passage of tropical or extratropical cyclone;
during the passage of a tornado (thrombus, then rnado);
during a local or frontal thunderstorm.

strong storm with a speed of 24.5-28.4 m/s (10 points);
severe storm with a speed of 28.5-32.6 m/s (11 points).

Subtropical storm
tropical storm
Hurricane ( Atlantic Ocean)
Typhoon (Pacific Ocean).

Actions of the population in the event of a threat and during hurricanes, storms and tornadoes.

Conclusion

List of used literature.

Dangerous atmospheric phenomena (signs of approach, damaging factors, preventive measures and protective measures)

Meteorological and agrometeorological hazards

Meteorological and agrometeorological hazards are divided into:

storms (9-11 points):

hurricanes (12-15 points):

tornadoes;

vertical vortices;

large hail;

heavy rain (rain);

heavy snowfall;

heavy ice;

severe frost;

severe snowstorm;

heatwave;

heavy fog;

frosts.

Fog is the concentration of small drops of water or ice crystals in the surface layer of the atmosphere from air saturated with water vapor as it cools. In fogs, horizontal visibility is reduced to 100 m or less. Depending on the horizontal visibility range, there is heavy fog (visibility up to 50 m), moderate fog (visibility less than 500 m) and light fog (visibility from 500 to 1000 m).

A slight clouding of the air with horizontal visibility of 1 to 10 km is called a veil. The veil can be strong (visibility 1-2 km), moderate (up to 4 km) and weak (up to 10 km). Fogs are distinguished by origin: advective and radiation. Deteriorating visibility complicates the work of transport - flights are interrupted, the schedule and speed of ground transport changes. Drops of fog, settling on the surface or ground objects under the influence of gravity or air flow, moisten them. There have been repeated cases of overlapping of insulators of high-voltage power lines as a result of drops of fog and dew settling on them. Fog drops, like dew drops, are a source of additional moisture for field plants. As the droplets settle on them, they maintain high relative humidity around them. On the other hand, drops of fog, settling on plants, contribute to the development of rotting.

At night, fogs protect vegetation from excessive cooling due to radiation and weaken the harmful effects of frost. During the day, fogs protect vegetation from solar overheating. The settling of fog droplets on the surface of machine parts leads to damage to their coatings and corrosion.

Based on the number of days with fog, Russia can be divided into three parts: mountainous regions, central highlands and lowland regions. The frequency of fogs increases from south to north. A slight increase in the number of days with fog is observed in spring. Fogs of all types can be observed at both negative and positive soil surface temperatures (from 0 to 5°C).

Ice is an atmospheric phenomenon that forms as a result of freezing drops of supercooled rain or fog on the surface of the earth and objects. Is a layer dense ice, transparent or matte, which grows on the windward side.

The most significant icy conditions are observed during the passage of southern cyclones. When cyclones move from Mediterranean Sea to the east and filling them over the Black Sea, black ice is observed in the south of Russia.

The duration of black ice varies - from parts of an hour to 24 hours or more. The formed ice remains on objects for a long time. As a rule, black ice forms at night at negative air temperatures (from 0° to - 3°C). Black ice along with strong wind causes significant damage to the household: wires break under the weight of icing, telegraph poles fall, trees die, traffic stops, etc.

Frost is an atmospheric phenomenon that is the deposition of ice on thin long objects (tree branches, wires). There are two types of frost: crystalline and granular. The conditions of their formation are different. Crystalline frost is formed during fog as a result of sublimation (the formation of ice crystals directly from water vapor without its transition to a liquid state or during rapid cooling below 0 ° C) of water vapor, consists of ice crystals. Their growth occurs on the windward side of objects in light winds and temperatures below - 15°C. The length of the crystals, as a rule, does not exceed 1 cm, but can reach several centimeters. Granular frost is snow-like loose ice that grows on objects in foggy, mostly windy weather.

It has sufficient strength. The thickness of this frost can reach many centimeters. Most often, crystalline frost occurs in the central part of the anticyclone with high relative humidity air below the inversion layer. According to the conditions of formation, granular frost is close to glaze. Frost is observed throughout Russia, but is distributed unevenly, since its formation is influenced by local conditions - terrain height, relief shape, slope exposure, protection from the prevailing moisture-carrying flow, etc.

Due to the low density of frost (volume density from 0.01 to 0.4), the latter only causes increased vibration and sagging of power and communication wires, but can also cause their breaks. Frost poses the greatest danger to communication lines during strong winds, since the wind creates additional load on the wires, which sag under the weight of deposits, and the risk of their breakage increases.

A blizzard is an atmospheric phenomenon that is the transfer of snow over the surface of the earth by the wind with deterioration of visibility. There are such snowstorms as drifting snow, when most snowflakes rise a few centimeters above the snow cover; a blowing snow, if the snowflakes rise to 2 m or higher. These two types of snowstorms occur without snow falling from the clouds. And, in the end, a general, or upper, snowstorm - snowfall with strong winds. Snowstorms reduce visibility on the roads and interfere with transport.

A thunderstorm is a complex atmospheric phenomenon in which electrical discharges (lightning) occur in large rain clouds and between the clouds and the ground, which are accompanied by a sound phenomenon - thunder, winds and rainfall, often hail. Lightning strikes damage ground objects, power lines and communications. Squalls and downpours, floods and hail accompanying thunderstorms cause damage to agriculture and some areas of industry. There are intramass thunderstorms and thunderstorms that occur in areas of atmospheric fronts. Intramass thunderstorms are usually short-lived and occupy a smaller area than frontal thunderstorms. They arise due to strong heating of the underlying surface. Thunderstorms in the area atmospheric front differ in that they often appear in the form of chains of thunderstorm cells that move parallel to each other, covering a large area.

They occur on cold fronts, occlusion fronts, and also on warm fronts in warm, humid, typically tropical air. The zone of frontal thunderstorms is tens of kilometers wide with a front length of hundreds of kilometers. Approximately 74% of thunderstorms are observed in the frontal zone, other thunderstorms are intramass.

During a thunderstorm you should:

in the forest, take refuge among low trees with dense crowns;

in the mountains and open area hide in a hole, ditch or ravine;

all large metal objects fold 15-20 m away from you;

having taken refuge from the thunderstorm, sit down with your legs tucked under you and your head down on your legs bent at the knees, with your feet together;

put a plastic bag, branches or spruce branches, stones, clothes, etc. under yourself. isolating itself from the soil;

on the way, the group should disperse, walk one at a time, slowly;

in the shelter, change into dry clothes, or, as a last resort, thoroughly wring out the wet ones.

During a thunderstorm you cannot:

take shelter near solitary trees or trees that protrude above others;

lean against or touch rocks and steep walls;

stop at the edges of the forest, large clearings;

walk or stop near bodies of water and in places where water flows;

hide under rock overhangs;

run, fuss, move in a dense group;

wear wet clothes and shoes;

stay on high ground;

be near watercourses, in crevices and cracks.

blizzard

A snow storm is one of the types of hurricane, characterized by significant wind speeds, which contributes to the movement of huge masses of snow through the air, and has a relatively narrow range of action (up to several tens of kilometers). During a storm, visibility deteriorates sharply, and transport links, both intracity and intercity, may be interrupted. The duration of the storm varies from several hours to several days.

Blizzards, blizzards, and blizzards are accompanied by sudden changes in temperature and snowfall with strong gusts of wind. Temperature changes, snow and rain at low temperatures and strong winds create conditions for icing. Power lines, communication lines, roofs of buildings, various types of supports and structures, roads and bridges are covered with ice or wet snow, which often causes their destruction. Ice formations on the roads make it difficult, and sometimes even completely prevent the operation of road transport. Pedestrian movement will be difficult.

Snow drifts occur as a result of heavy snowfalls and blizzards, which can last from several hours to several days. They cause disruption of transport communications, damage to communication and power lines, and negatively affect economic activity. Snow drifts are especially dangerous when avalanches descend from the mountains.

The main damaging factor of such natural Disasters is the effect of low temperature on the human body, causing frostbite and sometimes freezing.

In the event of an immediate threat, the population is notified, the necessary forces and means, road and utility services are put on alert.

A blizzard, snowstorm or blizzard can last for several days, so it is recommended to create a supply of food, water, fuel in the house in advance, and prepare emergency lighting. You can leave the premises only in exceptional cases and not alone. Restrict movement, especially in rural areas.

You should only travel by car on main roads. In the event of a sharp increase in wind, it is advisable to wait out the bad weather in locality or near it. If the machine breaks down, do not move out of sight from it. If further movement is impossible, you should mark a parking lot, stop (with the engine facing upwind), and cover the engine on the radiator side. In case of heavy snowfall, make sure that the car is not covered with snow, i.e. Rake snow as needed. The car engine must be periodically warmed up to avoid it from “defrosting”, while preventing exhaust gases from entering the cabin (body, interior), for this purpose, make sure that the exhaust pipe is not blocked with snow. If there are several cars, it is best to use one car as a shelter, and drain the water from the engines of the remaining cars.

Under no circumstances should you leave your shelter (car); in heavy snow, landmarks may be lost after several tens of meters.

You can wait out a blizzard, blizzard or blizzard in a shelter equipped with snow. It is recommended to build a shelter only in open areas, where snow drifts are excluded. Before taking cover, you need to find landmarks on the ground in the direction of the nearest housing and remember their location.

Periodically it is necessary to control the thickness of the snow cover by piercing the ceiling of the shelter, and clear the entrance and ventilation hole.

You can find an elevated, steadily standing object in an open and snowless area, hide behind it, and constantly throw away and trample down the growing snow mass with your feet.

IN critical situations It is permissible to completely bury yourself in dry snow, for which you should put on all your warm clothes, sit with your back to the wind, cover yourself with plastic wrap or a sleeping bag, pick up a long stick and let the snow cover you. Constantly clear the ventilation hole with a stick and expand the volume of the resulting snow capsule in order to be able to get out of the snow drift. A guide arrow should be placed inside the resulting shelter.

Remember that a blizzard, due to multi-meter snow drifts and drifts, can significantly change appearance terrain.

The main types of work during snow drifts, blizzards, blizzards or blizzards are:

searching for missing people and providing them with first aid, if necessary;

clearing roads and areas around buildings;

providing technical assistance to stranded drivers;

elimination of accidents on utility and energy networks.

Hail is an atmospheric phenomenon associated with the passage of cold fronts. Occurs during strong rising air currents during warm seasons. Droplets of water falling on greater height with air currents, freeze, and ice crystals begin to grow on them in layers. The drops become heavier and begin to fall down. When falling, they increase in size from merging with droplets of supercooled water. Sometimes hail can reach the size chicken egg. Typically, hail falls from large rain clouds during a thunderstorm or rainstorm. It can cover the ground with a layer of up to 20-30 cm. The number of days with hail increases in mountainous areas, on hills, and in areas with very rough terrain. Hail falls mainly in the afternoon on relatively small areas several kilometers away. Hail usually lasts from a few minutes to a quarter of an hour. Hail causes significant property damage. It destroys crops, vineyards, knocks flowers and fruits off plants. If hailstones are large in size, they can cause destruction of buildings and loss of life. IN given time Methods for identifying hail clouds have been developed, and a hail control service has been created. Dangerous clouds are “shot” with special chemicals.

Dry wind is a hot and dry wind with a speed of 3 m/s or more, with high air temperatures up to 25°C and low relative humidity up to 30%. Dry winds are observed in partly cloudy weather. Most often they occur in the steppes on the periphery of anticyclones that form above Northern Caucasus and Kazakhstan.

The highest dry wind speeds were observed during the day, and the lowest at night. Dry winds cause great damage to agriculture: they increase the water balance of plants, especially when there is a lack of moisture in the soil, since intensive evaporation cannot be compensated by the supply of moisture through the root system. With prolonged exposure to dry winds, the above-ground parts of plants turn yellow, the foliage curls, and they wilt and even die of field crops.

Dust, or black, storms - transference large quantity dust or sand by strong winds. They occur during dry weather due to the movement of sprayed soil over vast distances. The occurrence, frequency and intensity of dust storms are greatly influenced by orography, the nature of the soil, forest cover and other features of the area.

More often dust storms occur from March to September. The most intense and dangerous spring dust storms occur during a prolonged absence of rain, when the soil dries out and the plants are still poorly developed and do not form a continuous cover. At this time, storms blow away soil over vast areas. Horizontal visibility is reduced. S.G. Popruzhenko investigated a dust storm in 1892 in southern Ukraine. This is how he described it: “A dry, strong east wind for several days tore up the earth and drove away masses of sand and dust. The crops, which turned yellow from the dry air, were cut at the root, like a sickle, but the roots could not survive. The earth was demolished. up to 17 cm depth. Channels are filled up to 1.5 m.

Hurricane

A hurricane is a wind of destructive force and considerable duration. A hurricane occurs suddenly in areas with a sharp change in atmospheric pressure. Hurricane speed reaches 30 m/s or more. In terms of its harmful effects, a hurricane can be compared to an earthquake. This is explained by the fact that hurricanes carry colossal energy; the amount of energy released by an average hurricane in one hour can be compared with the energy of a nuclear explosion.

A hurricane can cover an area up to several hundred kilometers in diameter and can travel thousands of kilometers. At the same time, hurricane winds destroy strong and demolish light buildings, devastate sown fields, break wires and knock down power and communication line poles, damage highways and bridges, break and uproot trees, damage and sink ships, and cause accidents in public utility networks. . There were cases when hurricane winds threw trains off the rails and knocked down factory chimneys. Hurricanes are often accompanied by heavy rainfall, which causes flooding.

A storm is a type of hurricane. The wind speed during a storm is not much less than the speed of a hurricane (up to 25-30 m/s). Losses and destruction from storms are significantly less than from hurricanes. Sometimes a strong storm is called a storm.

A tornado is a strong small-scale atmospheric vortex with a diameter of up to 1000 m, in which the air rotates at a speed of up to 100 m/s, which has great destructive power (in the USA it is called a tornado).

On the territory of Russia, tornadoes are observed in the Central region, the Volga region, the Urals, Siberia, Transbaikalia, and the Caucasian coast.

A tornado is an upward vortex consisting of extremely rapidly rotating air mixed with particles and moisture, sand, dust and other suspended matter. On the ground, it moves in the form of a dark column of rotating air with a diameter of several tens to several hundred meters.

In the internal cavity of a tornado, the pressure is always low, so any objects that are in its path are sucked into it. average speed The tornado moves at 50-60 km/h, and as it approaches, a deafening roar is heard.

Strong tornadoes travel tens of kilometers and tear off roofs, uproot trees, lift cars into the air, scatter telegraph poles, and destroy houses. Notification of a threat is carried out by issuing the “Attention to all” signal with a siren and subsequent voice information.

Actions upon receiving information about an impending hurricane, storm or tornado - you should carefully listen to the instructions of the management body for civil emergency situations, which will indicate the expected time, strength of the hurricane and recommendations on rules of conduct.

Upon receipt of a storm warning, it is necessary to immediately begin carrying out preventive work:

strengthen insufficiently strong structures, close doors, dormer openings and attic spaces, cover the windows with boards or cover them with shields, and cover the glass with strips of paper or fabric, or, if possible, remove it;

in order to balance the external and internal pressure in the building, it is advisable to open doors and windows on the leeward side and secure them in this position;

It is necessary to remove things from roofs, balconies, loggias and window sills that could cause injury to people if they fall. Items located in courtyards must be secured or brought indoors;

It is also advisable to take care of emergency lamps - electric lamps, kerosene lamps, candles. It is also recommended to create supplies of water, food and medicine, especially dressings;

extinguish the fire in the stoves, check the condition of electrical switches, gas and water taps;

take pre-prepared places in buildings and shelters (in the case of tornadoes - only in basements and underground structures). Indoors, you need to choose the safest place - in the middle part of the house, in the corridors, on the ground floor. To protect against injury from glass fragments, it is recommended to use built-in cabinets, durable furniture and mattresses.

The safest place during a storm, hurricane or tornado is shelters, basements and cellars.

If a hurricane or tornado finds you in an open area, it is best to find any natural depression in the ground (ditch, hole, ravine or any notch), lie down at the bottom of the depression and press tightly to the ground. Leave the vehicle (no matter what you are in) and take refuge in the nearest basement, shelter or recess. Take measures to protect against heavy rainfall and large hail, as... hurricanes are often accompanied by them.

be on bridges, as well as in close proximity to facilities that use toxic, potent and flammable substances in their production;

take cover under isolated trees, poles, and come close to power line supports;

be near buildings from which tiles, slates and other objects are blown away by gusts of wind;

After receiving a message that the situation has stabilized, you should leave the house carefully; you need to look around to see if there are any overhanging objects or parts of structures, or broken electrical wires. It is possible that they are energized.

Unless absolutely necessary, do not enter damaged buildings, but if such a need arises, then this must be done carefully, making sure that there is no significant damage to stairs, ceilings and walls, fires, breaks in electrical wires, and you should not use elevators.

The fire should not be lit until it is certain that there is no gas leak. When outdoors, stay away from buildings, poles, high fences, etc.

The main thing in these conditions is not to give in to panic, to act competently, confidently and wisely, to prevent yourself and to restrain others from unreasonable actions, and to provide assistance to the victims.

The main types of injury to people during hurricanes, storms and tornadoes are closed injuries various areas bodies, bruises, fractures, concussions, wounds accompanied by bleeding.

Lecture topic: "Natural hazards and protection against them."

Plan.

General patterns and classification natural hazards.

Geological hazards.

Meteorological hazards.

Hydrological hazards.

Natural fires.

Space dangers.

1. TO natural hazards These include natural phenomena that pose a direct threat to the life and health of people (for example, floods, earthquakes, etc.).

Natural hazards have threatened the inhabitants of the Earth since the beginning of civilization.

Despite profound differences, all natural hazards are subject to certain general patterns:

Each type of hazard is characterized by a certain spatial location.

It has been established that the greater the intensity (power) of the danger, the less often it happens.

Each type of danger is preceded by some specific signs (harbingers).

Despite the unexpected nature of a natural hazard, its manifestation can be predicted and protective measures can be taken.

There is a relationship between natural hazards (one phenomenon can cause another).

Anthropogenic influence can lead to increased hazardous impacts.

A prerequisite for successful protection against natural hazards is the study of their causes and mechanisms. Knowing the essence of processes, you can predict them. Timely and accurate forecast– an important prerequisite for effective protection.

Based on localization, natural hazards are conventionally divided into groups:

geological (earthquakes, volcanic eruptions, landslides, mudflows, avalanches);

meteorological (storms, hurricanes, tornadoes, showers, frosts, hail);

hydrological (floods, tsunamis);

natural fires (forest, steppe and grain fires, peat, underground fires of fossil fuels);

cosmic (meteorite falls).

2. Earthquakes - These are tremors and vibrations of the earth's surface resulting from sudden displacements and ruptures in earth's crust or the upper part of the mantle and transmitted over long distances in the form of elastic vibrations.

Earthquake Science - seismology.

Earthquake source- this is a certain volume in the thickness of the Earth, within which energy is released. The center of the outbreak is a conventional point called hypocenter. Projection of the hypocenter onto the Earth's surface - epicenter, around which the greatest destruction occurs.

Hundreds of thousands of earthquakes are recorded around the globe every year. One earthquake occurs approximately every 30 seconds. Most of them are weak and we don't notice them.

The strength of earthquakes is assessed a) by seismic energy and b) by the intensity of destruction on the Earth's surface.

In 1935, C. Richter (professor at the California Institute of Technology) proposed estimating the energy of an earthquake magnitude. Richter proposed a 9-magnitude scale (in Japan they use a 7-magnitude scale). The magnitude value is determined from observations at seismic stations. Ground vibrations are recorded by special instruments - seismographs.

According to the international scale MSK-64 (Medvedev-Sponheier-Kernik), the strength of earthquakes is assessed in points depending on the intensity of destruction occurring on the Earth's surface (12-point scale). This scale is adopted in Russia.

Magnitude is indicated by Arabic numerals, and intensity by Roman numerals (for example, the intensity of the earthquake that occurred on December 7, 1988 in Spitak was estimated at IX-X points).

Earthquakes are distributed very unevenly across the earth's surface. Analysis of seismic and geographic data allows us to identify areas where earthquakes should be expected in the future and estimate their intensity. The seismic zoning map is an official document that should guide design organizations. In areas prone to earthquakes, earthquake-resistant or anti-seismic construction is carried out.

Currently, two seismic belts are known:

Mediterranean-Asian (Portugal, Italy, Greece, Turkey, Iran, Northern India)

Pacific (Sakhalin, Kuril ridge).

In Russia, the most dangerous areas are in the Baikal region, Kamchatka, the Kuril Islands, Southern Siberia and the North Caucasus.

Anti-seismic measures:

A) warning, prophylactic, carried out before a possible earthquake - study of the nature of earthquakes, mechanism, identification of precursors (increase in weak tremors, rise of water in wells, increase in radiation levels, restless behavior of animals); development of forecasting methods, training of the population, earthquake-resistant or anti-seismic construction, training of rescue services;

B) activities carried out immediately before, during and after an earthquake, i.e. actions in an emergency - rescue operations.

Actions of the population during an earthquake

Do not panic, act calmly and prudently.

Move away from tall buildings and power lines.

With the onset of an earthquake, people in their houses must urgently leave the premises (within 25-30 seconds) and go to open place (It is prohibited to use the elevator!).

If it is impossible to leave the building, stand in the doorway of the main internal wall. Turn off the gas, lights, water. After the tremors stop, leave the room.

Get involved in saving people.

Volcanic activity.

Volcanic activity occurs as a result of constant active processes occurring in the depths of the Earth. About 200 million people live dangerously close to active volcanoes.

The set of phenomena associated with the movement of magma in the earth's crust and on its surface is called volcanism.

Magma- This is a decomposed mass of predominantly silicate composition, formed in the deep zones of the Earth. When magma reaches the earth's surface, it erupts as lava. Lava differs from magma in the absence of gases that escape during an eruption. Volcanoes are geological formations that arise above channels and cracks in the earth's crust through which magma erupts onto the earth's surface. Magma chambers are located in the mantle at a depth of 50-70 km.

Volcanoes are divided into:

Active;

Asleep;

Extinct.

TO asleep These include volcanoes for which there is no information about eruptions, but they have retained their shape and local earthquakes occur beneath them.

Extinct- These are volcanoes without any volcanic activity.

Volcanic eruptions can be long-term or short-term.

There is a relationship between volcanic activity and earthquakes. Seismic tremors usually mark the beginning of an eruption. At the same time, lava fountains, hot lava flows, and hot gases pose a danger. Volcanic explosions can initiate landslides, avalanches, landslides, and tsunamis in the seas and oceans.

Preventive actions.

The measures consist of changing the nature of land use, building dams to divert lava flows, and bombarding a lava flow to mix the lava with the earth and turn it into a less liquid mass.

When volcanic activity begins, which can be predicted using modern equipment, it is necessary to evacuate the nearby population.

Landslide - this is a sliding displacement down a slope under the influence of gravity of soil masses that form the slopes of hills, mountains, river, lake and sea terraces. The triggers of landslide processes are earthquakes, volcanic eruptions, construction work, precipitation, weathering, etc. The danger of landslides is that huge masses of soil, suddenly shifting, can lead to the destruction of buildings and structures and large casualties.

The most tragic landslide occurred in 1920 in China. After a strong earthquake in the mountains, thousands of cubic meters of forest filled up valleys, covered cities and villages, which led to the death of 200 thousand people.

Protection measures:

installation of engineering structures (retaining walls);

security and restrictive measures (prohibition of construction, blasting, etc.).

In dangerous places, a surveillance and warning system for the population, as well as emergency rescue services, is provided.

Sat down – short-term stormy floods on mountain rivers, having the character of mud-stone flows. Mudflows can be caused by earthquakes, heavy snowfalls, rainstorms, or intense snow melting. The main danger is the enormous kinetic energy of mud flows, the speed of which can reach 15 km/h.

Mudflows occur suddenly, grow quickly and usually last from 1 to 3 hours, sometimes 6-8 hours. Mudflows are predicted based on observations from previous years and weather forecasts.

TO preventive anti-mudflow measures include: construction of hydraulic structures (mudflow retention and mudflow control), melt water drainage, forest planting work, regulation of forest cutting, etc.

In mudflow-prone areas, automatic warning systems about mudflow hazards are created and appropriate action plans are developed.

snow avalanche is a snow avalanche, a mass of snow falling or sliding down mountain slopes under the influence of some influence and carrying new masses of snow along its path. Snow avalanches common in mountainous areas. The danger of an avalanche lies in the high kinetic energy of the avalanche mass, which has enormous destructive power. The avalanche speed can reach 100 m/s, on average 20-30 m/s.

Protection methods: use of snow-retaining shields, planting forests, artificially triggering an avalanche at a pre-selected time and subject to safety measures (directional explosions, strong sound sources), etc.

3. Meteorological hazards:

strong wind (including storm, hurricane, tornado);

heavy rain (with precipitation of 50 mm or more for 12 hours or more);

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

strong snowstorms (with wind speeds of 15 m/s or more);

large hail (hailstone diameter 20 mm or more);

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

  severe frosts or extreme heat;

Wind- This is the movement of air relative to the ground. Air movement is directed from high pressure to low. An area of ​​low pressure in the atmosphere with a minimum in the center is a cyclone. The weather during a cyclone is more cloudy, with strong winds. Anticyclone is an area of ​​high pressure with a maximum in the center. The anticyclone is characterized by partly cloudy, dry weather and weak winds.

To assess wind strength in points by its effect on ground objects or by sea waves, the English admiral F. Beaufort in 1805 developed a conventional scale, which, after changes and clarifications in 1963, was adopted by the World Meteorological Organization and is widely used in synoptic practice (12-point scale). On this scale 0 points. – calm, wind speed 0-0.2 m/s.

9 b. – storm or strong storm, wind speed 20.8-24.4 m/s, wind tears off tiles, minor damage.

12 b. – hurricane, wind speed of 32.7 m/s or more, wind of great destructive force.

Squalls– short-term increases in wind speed up to 20-30 m/s.

Typhoons– hurricanes that occur over the Pacific Ocean. The average duration is 9-12 days.

Tornado is an atmospheric vortex that arises in a thundercloud and spreads in the form of a dark arm or trunk towards the surface of land or sea. At the top it has a funnel-shaped expansion that merges with the clouds. Like hurricanes, tornadoes are identified from weather satellites. They often occur suddenly and are difficult to predict.

In the USA, tornadoes over land are called tornado.

4. Flood - this is a significant flooding of an area with water as a result of rising water levels in a river, lake or sea, caused by various reasons. Flooding is the most common natural hazard.

The causes of flooding are:

flood; - flood; - storm water; - mash; - gluttonous; - mudflows; - surge; - in case of accidents at hydraulic structures.

High water– a relatively long increase in the water content of rivers, repeated annually in the same season, accompanied by an increase in water level. It occurs due to the spring melting of snow and ice in the mountains.

Flood– a relatively short-term and non-periodic rise in water levels. Occurs due to rain, winter thaws with wet snow.

Floods are often caused by blockage of the riverbed with large pieces of ice during ice drift - congestion(happens at the end of winter or spring.) or by clogging the channel with internal loose ice under a stationary ice cover and the formation of an ice plug - glutton(happens at the beginning of winter).

Sometimes floods occur under the influence of winds, driving water from the sea and causing an increase in the level due to the retention of water brought by the river at the mouth - surge floods.

Tsunami- These are gravitational waves of very long length, resulting from the upward or downward displacement of extended sections of the bottom during strong underwater earthquakes (less often volcanic eruptions).

Actions of the population during a flood

The most effective method of protection is evacuation. Before evacuating, you need to turn off electricity, gas, and water in your houses; take a supply of food, medicine, documents and leave along the specified route. In the event of a sudden flood, you must immediately leave the house and take the nearest safe, elevated place, hanging a warning white or colored banner.

After the water has subsided, when returning home, you must follow safety measures: do not come into contact with electrical wiring, do not use food that has fallen into the water. When entering the house, ventilate. It is prohibited to turn on gas and electricity.

5 . Among natural fires highlight:

• fires of steppe and grain massifs;

  peat;

  underground fossil fuel fires.

In 90-97 cases out of 100, the culprits of a fire are people who do not show due caution when using fire in places of work and leisure. Fires caused by lightning account for 2% of the total.

Forest fires are uncontrolled burning of vegetation that spreads spontaneously throughout a forest area. Large forest fires develop during periods of extreme danger in the forest, during prolonged and severe drought. Their development is favored by windy weather and cluttered forests.

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 fires at the beginning of their development are grassroots in nature and, if certain conditions are created, they turn into crown fires and soil fires. According to the speed of fire spread, low and high fires are divided into stable and fluent from 0.02 m/s to 2 m/s. The intensity of combustion depends on the state of the supply of combustible materials, the slope of the terrain, the time of day and especially the strength of the wind.

Runaway ground fires are characterized by the rapid advancement of the edge of the fire when dry grass and fallen leaves burn. They occur more often in the spring, usually do not damage mature trees, but often create the threat of crown fires. In stable ground fires, the edge moves slowly and a lot of smoke is generated, which indicates the heterogeneous nature of the combustion. They are typical for the second half of summer.

Peat(underground) fire - when it burns the peat layer of marshy and swampy soils. Spread speed – 1-3 m/min. A characteristic feature is flameless combustion of peat with the release of a large amount of heat. They occur from lightning, spontaneous combustion of peat under unfavorable weather conditions (high air temperature, drought).

6 . Among the serious dangers that threaten humans and all life on Earth, we should highlight those associated with collisions of the planet with cosmic bodies: asteroids, comets, meteorites.

Asteroids- these are small planets orbiting the Sun, whose diameter ranges from 1-1000 km.

Comet- a relatively small celestial body compared to an asteroid. Most comets move around the Sun in elongated ellipses: when approaching the Sun, under the influence of its heat, they release gases that form a luminous shell around the nucleus - the head of the comet, and develop a tail directed in the direction opposite to the Sun. As the comet moves away from the Sun, the tail gradually dissipates into outer space.

Meteorite- a small solid body that flew into the Earth’s atmosphere at a speed of tens of km/s and did not have time to completely evaporate or disperse in the Earth’s atmosphere.

Bolide– a very bright meteor with a long luminous tail; the flight of a fireball is sometimes accompanied by a strong sound and ends with a meteorite falling onto the earth's surface.

Currently, about 300 cosmic bodies are known that can cross the Earth's orbit. In total, according to astronomers’ forecasts, there are ≈ 300 thousand asteroids and comets in space. The meeting of the Earth with such celestial bodies poses a serious threat to the entire biosphere. According to calculations, the impact of an asteroid with a diameter of about 1 km is accompanied by the release of energy tens of times greater than the entire nuclear potential available on Earth.

The main means of combat is nuclear missile technology. It is proposed to develop a system of planetary protection against asteroids and comets, which is based on changing the trajectory of a dangerous space object or destroying it into several parts. For this purpose, it is planned to use intercontinental ballistic missiles with a nuclear warhead.

Lecture “Biological and social emergencies”

Biological emergencies include epidemics, epizootics and epiphytoties.

Epidemic is a widespread spread of an infectious disease among people, significantly exceeding the incidence rate usually recorded in a given territory.

A pandemic is an unusually large spread of morbidity, both in level and in scope, covering a number of countries, entire continents and even the globe.

Infectious diseases are divided into:

infections of internal organs (viral hepatitis (Botkin's disease), brucellosis, typhoid fever, dysentery, salmonellosis);

respiratory tract infections (tuberculosis, various pneumoconiosis);

blood or transmissible (HIV);

infections of the external integument (dermatitis, eczema, psoriasis, fungal diseases).

The basis for the general biological classification of infectious diseases is their division, first of all, in accordance with the characteristics of the pathogen (anthroponoses, zoonoses), as well as division into vector-borne and non-transmissible. Infectious diseases by type of pathogen - viral diseases, rickettsioses, bacterial infections, protozoal diseases, helminthiasis, tropical microses, diseases of the blood system.

Epizootics are infectious diseases of animals. These diseases have such characteristics as the presence of a specific pathogen, cyclical development, the ability to be transmitted from an infected animal to a healthy one and become epizootic.

Epizootic focus is the location of the source of the infectious agent in a certain area of ​​the area, where, in this situation, transmission of pathogens to susceptible animals is possible.

According to the breadth of distribution, the epizootic process occurs in three forms: sporadic incidence, epizootic, panzootic.

Sporadia is isolated, accidental manifestations of an infectious disease that are not related to each other by a single source of infectious agent (the lowest degree of intensity of the disease).

During an epizootic, an average degree of disease intensity is observed, which is accompanied by the spread of diseases in the farm, district, or region. Such diseases are characterized by a common source of the infectious agent, simultaneity of damage, periodicity, and seasonality.

According to the epizootic classification, all infectious animal diseases are divided into 5 groups:

Group 1 – nutritional infections, transmitted through soil, food, water. The organs of the digestive system are mainly affected. The pathogen is transmitted through infected feed, manure, and soil (anthrax, foot-and-mouth disease, glanders, brucellosis).

Group 2 – respiratory infections (aerogenic) damage to the mucous membranes of the respiratory tract and lungs. The main route of transmission is airborne (bird flu, exotic pneumonia, sheep and goat pox, canine distemper).

Group 3 – vector-borne infections, transmitted by blood-sucking arthropods (encephalomyelitis, tularemia, equine infectious anemia).

Group 4 – infections transmitted through the outer skin without the participation of carriers (tetanus, rabies, cowpox).

Group 5 – infectious diseases with unknown routes of infection.

Panzootic is the highest degree of development of epizootic, characterized by an unusually wide spread of the disease, covering one state, several countries, and a continent.

To assess the scale of plant diseases, concepts such as epiphytoty and panphytoty are used.

Epiphytoty is the spread of infectious plant diseases over significant distances over a certain period of time.

Panphytotia is a mass disease covering several countries or continents.

The most dangerous diseases are stem rust of cereals and late blight of potatoes.

Plant diseases are classified according to the following criteria:

Place or phase of development in plants (diseases of seeds, seedlings, seedlings, mature plants);

Place of occurrence (local, local, general);

Course (acute, chronic);

Affected crop;

Cause of occurrence (infectious or not).

All pathological changes in plants manifest themselves in various forms: rot, mummification, wilting, plaque, growths.

The results of the interaction of certain atmospheric processes, which are characterized by certain combinations of several meteorological elements, are called atmospheric phenomena.

Atmospheric phenomena include: thunderstorm, blizzard, dust storm, fog, tornado, aurora, etc.

All meteorological phenomena monitored at meteorological stations are divided into the following groups:

hydrometeors , are a combination of rare and solid, or both, water particles suspended in the air (clouds, fogs) that fall in the atmosphere (precipitation); which settle on objects near the earth's surface in the atmosphere (dew, frost, ice, frost); or raised by the wind from the surface of the earth (blizzard);

lithometeors , are a combination of solid (non-water) particles that are lifted by the wind from the earth's surface and transported over a certain distance or remain suspended in the air (dust blowing snow, dust storms, etc.);

electrical phenomena, which include manifestations of the action of atmospheric electricity that we see or hear (lightning, thunder);

optical phenomena in the atmosphere that arise as a result of reflection, refraction, scattering and diffraction of solar or monthly light (halo, mirage, rainbow, etc.);

unclassified (miscellaneous) phenomena in the atmosphere, which are difficult to attribute to any of the types indicated above (squall, whirlwind, tornado).

Vertical heterogeneity of the atmosphere. The most important properties of the atmosphere

According to the nature of temperature distribution with height, the atmosphere is divided into several layers: troposphere, stratosphere, mesosphere, thermosphere, exosphere.

Figure 2.3 shows the course of temperature changes with distance from the earth's surface in the atmosphere.

A – altitude 0 km, t = 15 0 C; B – altitude 11 km, t = -56.5 0 C;

C – altitude 46 km, t = 1 0 C; D – altitude 80 km, t = -88 0 C;

Figure 2.3 – Temperature variation in the atmosphere

Troposphere

The thickness of the troposphere in our latitudes reaches 10-12 km. The bulk of the atmospheric mass is concentrated in the troposphere, so various weather phenomena are most pronounced here. In this layer there is a continuous decrease in temperature with height. It averages 6 0 C for every 1000 g. The sun's rays greatly heat the earth's surface and the adjacent lower layers of air.

The heat that comes from the earth is absorbed by water vapor, carbon dioxide, and dust particles. Higher up, the air is thinner, there is less water vapor in it, and the heat radiated from below has already been absorbed by the lower layers - so the air there is colder. Hence the gradual drop in temperature with height. In winter, the surface of the earth cools greatly. This is facilitated by snow cover, which reflects most of the sun's rays and at the same time radiates heat to higher layers of the atmosphere. Therefore, the air near the surface of the earth is often colder than above. The temperature increases slightly with altitude. This is the so-called winter inversion (reverse temperature change). In summer, the earth is heated by the sun's rays strongly and unevenly. Air streams and vortices rise from the hottest areas. To replace the air that has risen, air flows from less heated areas, in turn, being replaced by air that falls from above. Convection occurs, which causes mixing of the atmosphere in the vertical direction. Convection destroys fog and reduces dust in the lower layer of the atmosphere. Thus, thanks to vertical movements in the troposphere, constant mixing of air occurs, which ensures the constancy of its composition at all altitudes.

The troposphere is a place of constant formation of clouds, precipitation and other natural phenomena. Between the troposphere and stratosphere there is a thin (1 km) transition layer called the tropopause.

Stratosphere

The stratosphere extends to an altitude of 50-55 km. The stratosphere is characterized by an increase in temperature with height. Up to an altitude of 35 km, the temperature rises very slowly; above 35 km, the temperature rises quickly. The increase in air temperature with altitude in the stratosphere is associated with absorption solar radiation ozone. At the upper limit of the stratosphere, the temperature fluctuates sharply depending on the time of year and latitude. The rarefaction of air in the stratosphere causes the sky there to be almost black. Always in the stratosphere good weather. The sky is cloudless and only at an altitude of 25-30 km pearlescent clouds appear. In the stratosphere there is also intense air circulation and vertical movements are observed.

Mesosphere

Above the stratosphere is the mesosphere layer, up to approximately 80 km. Here the temperature drops with altitude to several tens of degrees below zero. Due to the rapid drop in temperature with height, there is highly developed turbulence in the mesosphere. At altitudes close to the upper boundary of the mesosphere (75-90 km), noctilucent clouds are observed. They are most likely composed of ice crystals. At the upper boundary of the mesosphere, air pressure is 200 times less than at the earth's surface. Thus, in the troposphere, stratosphere and mesosphere together, up to an altitude of 80 km, there is more than 99.5% of the total mass of the atmosphere. The higher layers account for a small amount of air.

Thermosphere

The upper part of the atmosphere, above the mesosphere, is characterized by very high temperatures and is therefore called the thermosphere. It differs, however, in two parts: the ionosphere, which extends from the mesosphere to altitudes of about a thousand kilometers, and the exosphere, which is located above it. The exosphere passes into the earth's corona.

The temperature here increases and reaches + 1600 0 C at an altitude of 500-600 km. Gases here are very rarefied, molecules rarely collide with each other.

The air in the ionosphere is extremely rarefied. At altitudes of 300-750 km, its average density is about 10 -8 -10 -10 g/m 3 . But even with such a small density of 1 cm 3, the air at an altitude of 300 km still contains about one billion molecules or atoms, and at an altitude of 600 km - over 10 million. This is several orders of magnitude greater than the content of gases in interplanetary space.

The ionosphere, as the name suggests, is characterized by a very strong degree of ionization of the air - the ion content here is many times greater than in the lower layers, despite the greater general rarefaction of the air. These ions are mainly charged oxygen atoms, charged nitrogen oxide molecules, and free electrons.

In the ionosphere, several layers or regions with maximum ionization are distinguished, especially at altitudes of 100-120 km (layer E) and 200-400 km (layer F). But even in the spaces between these layers, the degree of ionization of the atmosphere remains very high. The position of the ionospheric layers and the concentration of ions in them change all the time. Concentrations of electrons in particularly high concentrations are called electron clouds.

The electrical conductivity of the atmosphere depends on the degree of ionization. Therefore, in the ionosphere, the electrical conductivity of air is generally 10-12 times greater than that of the earth’s surface. Radio waves are subject to absorption, refraction and reflection in the ionosphere. Waves longer than 20 m cannot pass through the ionosphere at all: they are reflected by electron clouds in the lower part of the ionosphere (at altitudes of 70-80 km). Medium and short waves are reflected by higher ionospheric layers.

It is due to reflection from the ionosphere that long-distance communication on short waves is possible. Repeated reflection from the ionosphere and the earth's surface allows short waves to propagate in a zigzag manner over long distances, bending around the surface Globe. Since the position and concentration of ionospheric layers are constantly changing, the conditions for absorption, reflection and propagation of radio waves also change. Therefore, for reliable radio communications, continuous study of the state of the ionosphere is necessary. Observation of the propagation of radio waves is the means for such research.

In the ionosphere, auroras and the glow of the night sky, which is close in nature to them in nature, are observed - constant luminescence of atmospheric air, as well as sharp fluctuations in the magnetic field - ionospheric magnetic drills.

Ionization in the ionosphere occurs under the influence of ultraviolet radiation from the Sun. Its absorption by molecules of atmospheric gases leads to the formation of charged atoms and free electrons. Fluctuations in the magnetic field in the ionosphere and auroras depend on fluctuations in solar activity. Changes in solar activity are associated with changes in the flow of corpuscular radiation that comes from the Sun into the earth's atmosphere. Namely, corpuscular radiation is of primary importance for these ionospheric phenomena. The temperature in the ionosphere increases with altitude to very high values. At altitudes close to 800 km it reaches 1000°.

Speaking about high temperatures of the ionosphere, they mean that particles of atmospheric gases move there with very high speeds. However, the air density in the ionosphere is so low that a body that is in the ionosphere, such as a satellite, will not be heated by heat exchange with the air. The temperature regime of the satellite will depend on its direct absorption of solar radiation and on the release of its own radiation into the surrounding space.

Exosphere

Atmospheric layers above 800-1000 km are distinguished by the name exosphere (external atmosphere). The speeds of movement of gas particles, especially light ones, are very high here, and due to the extreme rarefaction of the air at these altitudes, the particles can fly around the Earth in elliptical orbits without colliding with each other. Individual particles can have speeds sufficient to overcome gravity. For uncharged particles, the critical speed will be 11.2 km/s. Such particularly fast particles can, moving along hyperbolic trajectories, fly out of the atmosphere into outer space, “slip out,” and dissipate. Therefore, the exosphere is also called the scattering sphere. It is mainly the hydrogen atoms that are susceptible to slipping.

It was recently assumed that the exosphere, and with it the Earth’s atmosphere in general, ends at altitudes of about 2000-3000 km. But observations from rockets and satellites have shown that hydrogen that escapes from the exosphere forms what is called the Earth's corona around the Earth, which extends to more than 20,000 km. Of course, the density of gas in the earth's corona is negligible.

With the help of satellites and geophysical rockets, the existence in the upper part of the atmosphere and in near-Earth space of the Earth's radiation belt, which begins at an altitude of several hundred kilometers and extends tens of thousands of kilometers from the earth's surface, has been established. This belt consists of electrically charged particles - protons and electrons, captured by the Earth's magnetic field, which move at very high speeds. The radiation belt constantly loses particles in the earth's atmosphere and is replenished by flows of solar corpuscular radiation.

Based on its composition, the atmosphere is divided into homosphere and heterosphere.

The homosphere extends from the earth's surface to an altitude of about 100 km. In this layer, the percentage of main gases does not change with height. The molecular weight of the air remains constant.

The heterosphere is located above 100 km. Here oxygen and nitrogen are in an atomic state. The molecular weight of air decreases with height.

Does the atmosphere have an upper limit? The atmosphere has no boundaries, but, gradually becoming rarefied, passes into interplanetary space.