| Materials for OBZh lessons for grade 7 | Academic Year Plan | Natural Emergencies

Life Safety Basics
7th grade

Lesson 1
Natural Emergencies


Distinguish concepts "Dangerous natural phenomenon"  and "disaster".

Natural hazard   - this is an event of natural origin or the result of the activity of natural processes, which in its intensity, scale of distribution and duration can have a devastating effect on people, objects of the economy and the environment.

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

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

Disaster   - it is a destructive natural and (or) natural and anthropogenic phenomenon or process of a significant scale, as a result of which a life or health threat may or has arisen, destruction or destruction of material values \u200b\u200band environmental components.

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

An approximate ratio of the frequency of occurrence of natural hazards by their types.

Natural disasters are usually natural emergencies. They can occur independently of each other, and sometimes one natural disaster entails another. Earthquakes, for example, can cause avalanches or landslides. And some natural disasters occur due to human activities, sometimes unreasonable (an unsigned cigarette butt or an undamped bonfire, for example, often leads to a forest fire, explosions in the mountains when laying roads - to landslides, landslides, avalanches).

So, the occurrence of an emergency of a natural nature is a consequence of a natural phenomenon in which there is a direct threat to the life and health of people, material values \u200b\u200band the environment are destroyed and destroyed.

Typification of natural phenomena by degree of danger

Such phenomena can have a different origin, which became the basis for the classification of emergency situations of a natural nature, shown in Figure 1.

Each natural disaster in its own way affects a person and his health. Most people suffer from floods, hurricanes, earthquakes and droughts. And only about 10% of the damage caused to them falls on the remaining natural disasters.

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

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    • Natural emergencies: types and classification

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    In an emergency (emergency)   it is customary to understand the situation in a certain territory as a result of an accident, natural or other disaster that could result in or result in human casualties, damage to human health or the environment, significant material losses and violation of the living conditions of the population. Emergencies do not occur immediately, as a rule, they develop gradually from technological, social or natural occurrences.

    Natural disasters are usually unexpected. In a short time, they destroy territories, dwellings, communications, and cause hunger and disease. In recent years, emergencies of natural origin have a tendency to increase. In all cases of earthquakes, floods, landslides, their destructive power increases.

    Natural disasters are divided

    • Geophysical (endogenous) hazardous phenomena:  eruptions of volcanoes and geysers, earthquakes, releases of underground gases to the surface of the earth;
    • Geological (exogenous) hazardous phenomena:  landslides, screes, landslides, avalanches, mudflows, sloping runoff, subsidence of loess rocks, soil erosion, abrasion, subsidence (failure) of the earth's surface as a result of karuma kuruma, dust storms;
    • Meteorological hazards:  hurricanes (12 - 15 points), storms, storms (9 - 11 points), tornadoes (tornadoes), squalls, vertical whirlwinds, large hail, heavy rain (rain), heavy snow, heavy ice, severe frost, severe snowstorm, severe heat, heavy fog, drought, dry wind, frost;
    • Hydrological Hazards:  high levels of water (floods), floods, rain floods, congestion and blockages, wind surges, low water levels, early freezing and ice on navigable water bodies and rivers;
    • Marine hydrological hazards:  tropical cyclones (typhoons), tsunami, strong waves (5 points or more), strong sea level fluctuations, strong draft in ports, early ice cover and fast ice, pressure and intense ice drift, impenetrable (impenetrable) ice, icing of ships and port facilities , separation of coastal ice;
    • Hydrogeological hazards:  low groundwater levels, high groundwater levels;
    • Natural fires: forest fires, peat fires, fires of steppe and grain massifs, underground fires of combustible minerals;
    • Infectious diseases of people:  isolated cases of exotic and especially dangerous infectious diseases, group cases of dangerous infectious diseases, epidemic outbreak of dangerous infectious diseases, epidemic, pandemic, infectious diseases of people of unknown etiology;
    • Infectious diseases of animals:  isolated cases of exotic and especially dangerous infectious diseases, epizootics, panzootia, enzootia infectious diseases of farm animals of unknown etiology;
    • Infectious plant diseases:  progressive epiphytotia, panfitotia, diseases of agricultural plants of undiagnosed etiology, mass distribution of plant pests.

    Patterns of natural phenomena

    • Each type of emergency contributes to a certain spatial confinement;
    • The more intense a dangerous natural phenomenon, the less often it happens;
    • Each natural origin has predecessors - specific traits;
    • The appearance of a natural emergency, with all its unexpectedness, can be predicted;
    • It is often possible to provide both passive and active measures of protection against natural hazards.

    The role of anthropogenic influence on the manifestation of natural emergencies is great. Human activity upsets the balance in the natural environment. Now, when the scale of use of natural resources has sharply increased, the features of the global environmental crisis have become very noticeable. An important preventive factor in reducing the number of natural emergencies is maintaining the natural balance.

    All natural disasters are interconnected, such as earthquakes and tsunamis, tropical cyclones and floods, volcanic eruptions and fires, pasture poisoning, and cattle death. Taking protective measures against natural disasters, it is necessary to minimize the secondary consequences, and with the help of appropriate training, if possible eliminate them completely. The study of the causes and mechanisms of natural emergencies is a prerequisite for successful protection against them, the possibility of their prediction. An accurate and timely forecast is an important condition for effective protection against dangerous phenomena. Protection against natural disasters can be active (construction of engineering structures, reconstruction of natural objects, etc.) and passive (use of shelters),

    Natural geological hazards

    • earthquakes
    • landslides
    • sat down
    • snow avalanches
    • landslides
    • precipitation of the earth's surface as a result of karst phenomena.

    Earthquakes - These are underground shocks and vibrations of the earth's surface, resulting from tectonic processes, transmitted over long distances in the form of elastic vibrations. Earthquakes can cause volcanic activity, the fall of small celestial bodies, collapses, breakthroughs of dams and other causes.

    The causes of the earthquakes are not fully disclosed. Stresses arising under the action of deep tectonic forces deform the layers of the earth's rocks. They are compressed into folds, and when overloads reach critical levels, they are torn and mixed. A rupture of the earth's crust is formed, which is accompanied by a series of shocks and the number of shocks, and the gaps between them are very different. Shocks include foreshocks, main thrust and aftershocks. The main push has the greatest power. People perceive it as very long, although it usually lasts a few seconds.

    As a result of research, psychiatrists and psychologists obtained data that often aftershocks have a much more severe mental impact on people than the main impetus. There is a feeling of inevitability of trouble, a person is inactive, while he should defend himself.

    Earthquake source  - called a certain volume in the thickness of the Earth, within which energy is released.

    Hearth center  is a conditional point - a hypocenter or focus.

    Earthquake epicenter  - This is the projection of the hypocenter on the surface of the Earth. The largest destruction occurs around the epicenter, in the pleistoseist region.

    The energy of earthquakes is estimated by magnitude (lat. Magnitude). is a conditional quantity that characterizes the total amount of energy released in the earthquake source. The magnitude of the earthquake is estimated by the international seismic scale MSK - 64 (Merkalli scale). She has 12 conditional gradations - points.

    Earthquakes are predicted by recording and analyzing their “predecessors” - foreshocks (preliminary weak shocks), deformation of the earth's surface, changes in the parameters of geophysical fields, changes in the behavior of animals. Unfortunately, there are still no methods for reliable prediction of earthquakes. The time frame for the start of an earthquake can be 1-2 years, and the accuracy of predicting the location of an earthquake ranges from tens to hundreds of kilometers. All this reduces the effectiveness of measures to protect against earthquakes.

    In earthquake-prone areas, the design and construction of buildings and structures is taking into account the possibility of earthquakes. Earthquakes from 7 points and above are considered dangerous for structures, therefore, construction in areas with 9-point seismicity is uneconomical.

    Rocky soils are considered the most reliable in seismic terms. The stability of structures during earthquakes depends on the quality of building materials and work. There are requirements to limit the size of buildings, as well as requirements for taking into account the relevant rules and norms (SP and N), which are reduced to strengthening the design of structures under construction in earthquake-prone zones.

    Antiseismic Action Groups

    1. Preventive, preventive measures are the study of the nature of earthquakes, the determination of their predecessors, the development of methods for predicting earthquakes;
    2. Activities that are carried out immediately before the start of an earthquake, during and after it. The effectiveness of actions in the conditions of earthquakes depends on the level of organization of rescue operations, the training of the population, and the effectiveness of the warning system.

    A very dangerous immediate consequence of the earthquake is panic, during which people from fear can not consciously take measures to salvation and mutual assistance. Panic is especially dangerous in places of the greatest concentration of people - at enterprises, in educational institutions and in public places.

    Death and injuries occur when debris of destroyed buildings falls, as well as as a result of people being in the rubble and not receiving timely help. Earthquakes can cause fires, explosions, releases of hazardous substances, transport accidents, and other hazardous events.

    Volcanic activity  - This is the result of active processes that constantly occur in the bowels of the Earth. called the totality of phenomena that are associated with movement in the earth's crust and on its surface magma. Magma (Greek: thick ointment) is called a molten mass of silicate composition, which is formed deep in the Earth. When magma reaches the earth's surface, it erupts in the form of lava.

    There are no gases in the lava that escape during the eruption. That is what sets her apart from magma.

    Types of winds

    Vortex storms due to cyclonic activity, spread over large areas.

    Among the vortex storms are distinguished:

    • dusty
    • snowy.
    • heavy.

    Dusty (sand) storms  occur in deserts, in plowed steppes and are accompanied by the transfer of huge masses of soil and sand.

    Snow storms move large masses of snow through the air. They operate on a strip from several kilometers to several tens of kilometers. Great snowstorms occur in the steppe part of Siberia and on the plains of the European part of the Russian Federation. In Russia, winter storms are called blizzards, snowstorms, and snowstorms.

    Squalls  - short-term wind amplifications up to a speed of 20-30m / s. They are characterized by a sudden start and the same sudden end, short duration of actions and tremendous destructive force.

    Squall storms affect the European part of Russia both on land and at sea.

    Streaming storms  - local phenomena, having a small distribution. They are divided into stock and jet. During runoff storms, air masses move down the slope.

    Jet Storms  characterized by the horizontal movement of air or its movement up the slope. Most often they occur between the chains of mountains that connect the valleys.

    A tornado is an atmospheric vortex that occurs in a thundercloud. Then it spreads in the form of a dark “sleeve” towards land or sea. The upper part of the tornado has a funnel-shaped extension that merges with the clouds. When the tornado descends to the surface of the Earth, its lower part sometimes expands, resembling an overturned funnel. The height of the tornado is from 800 to 1500m. Rotating counterclockwise at a speed of up to 100 m / s and rising in a spiral, the air in a tornado draws in dust or water. A decrease in pressure inside the tornado leads to condensation of water vapor. Water and dust make the tornado visible. Its diameter above the sea is measured in tens of meters, and over land - in hundreds of meters.

    By structure, tornadoes are divided into dense (sharply limited) and vague (obscurely limited); in time and spatial effect - on small tornadoes of gentle action (up to 1 km), small (up to 10 km) and hurricane vortices (more than 10 km).

    Hurricanes, storms, tornadoes - extremely powerful elemental forces, in their destructive effect are comparable only to an earthquake. It is very difficult to predict the place and time of the appearance of the tornado, which gives them special danger and does not allow them to predict their consequences.

    Hydrological disasters

    High water  - annually repeated seasonal rise in water level.

    High water  - short-term and non-periodic increase in water level in a river or reservoir.

    Floods following one after another can cause floods and recent floods.

    Flooding is one of the most common natural hazards. They arise from a sharp increase in the amount of water in rivers as a result of melting snow or glaciers, due to heavy rains. Floods are often accompanied by clutter of the riverbed during ice drift (congestion) or clogging of the riverbed with an ice plug under a fixed ice cover (jam).

    On the coasts, floods can be caused by earthquakes, volcanic eruptions, and tsunamis. Floods caused by the action of winds, forcing water from the sea and raising the water level due to its delay at the mouth of the river, is called surge.

    Experts believe that people are at risk from floods if the water layer reaches 1m and its flow rate exceeds 1m / s. If the rise of water reaches 3m - this leads to the destruction of houses.

    Flooding can occur with complete calm. It can be caused by long waves that occur in the sea under the influence of a cyclone. In St. Petersburg, the islands in the Neva Delta have been flooded since 1703. more than 260 times.

    Floods on rivers differ in height of rise of water, flooding area and magnitude of damage: low (small), high (medium), outstanding (large), catastrophic. Low floods can recur in 10-15 years, high in 20-25 years, outstanding in 50-100 years, catastrophic in 100-200 years.

    They can last from several to 100 days.

    The flood in the Tigris and Euphrates Rivers in Mesopotamia, which occurred in 5600 years ago, had very serious consequences. In the Bible, the flood was called the Flood.

    Tsunamis are long-range marine gravitational waves resulting from shifts of large sections of the bottom during underwater earthquakes, volcanic eruptions, or other tectonic processes. In the region of their occurrence, the waves reach a height of 1-5 m, off the coast - up to 10 m, and in bays and river valleys - more than 50 m. Tsunamis extend inland to a distance of 3 km. The coast of the Pacific and Atlantic oceans is the main area of \u200b\u200btsunami manifestation. They produce very great damage and pose a threat to people.

    Breakwaters, embankments, harbors and jetties protect only partially from the tsunami. In the open sea, tsunamis are not dangerous for ships.

    Protecting the population from tsunamis - warnings of special services about the approach of waves, based on the advance registration of earthquakes by coastal seismographs.

    Forest, steppe, peat, underground fires are called landscape, or natural, fires. Forest fires are the most common, causing huge losses and resulting in human casualties.

    Forest fires are an uncontrolled burning of vegetation that spontaneously spreads over forest territory. In dry weather, the forest dries up so much that any careless handling of fire can cause a fire. In most cases, the culprit of the fire is a person. Forest fires are classified by the nature of the fire, the speed of propagation, and the size of the area covered by the fire.

    Depending on the nature of the fire and the composition of the forest, fires are divided into lower, upper and soil fires. At the beginning of its development, all fires are of a grassroots nature, and when certain conditions arise, they turn into high or soil fires. Riding fires are subdivided according to the parameters of the edge advancement (the combustion strip bordering the outer contour of the fire) into weak, medium, and strong. Ground and top fires according to the speed of spread of fire are divided into stable and runaway.

    Forest fire management methods. The main conditions for the effectiveness of the fight against forest fires are the assessment and forecast of the fire hazard in the forest. State forestry authorities monitor the state of protection on the territory of the forest fund.

    To organize a fire extinguishing, it is necessary to determine the type of fire, its characteristics, directions of its distribution, natural barriers (places that are especially dangerous for enhancing a fire), forces and means necessary to deal with it.

    When extinguishing a forest fire, the following main stages are distinguished: stopping, extinguishing the fire and littering the fire (preventing the possibility of sunburn from unexplained foci of burning).

    Two main fire fighting methods are distinguished by the nature of the effect on the combustion process: direct and indirect fire extinguishing.

    The first method is used to extinguish medium and low intensity with a propagation speed of up to 2 m / min. and a flame height of up to 1.5 m. The indirect method of extinguishing a fire in a forest is based on the creation of barriers along its path.

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

      - an unusually large spread of the incidence both in level and in the extent of spread, covering a number of countries, entire continents and even the entire globe.

    All infectious diseases are divided into four groups:

    • intestinal infections;
    • respiratory tract infections (aerosol);
    • blood (transmissible);
    • infections of the external integument (contact).

    Types of biological emergencies

    Epizootics.  Infectious diseases of animals - a group of diseases that have such common symptoms as the presence of a specific pathogen, the cyclical development, the ability to be transmitted from an infected animal to a healthy one and accept an epizootic spread.

    All infectious diseases of animals are divided into five groups:

    • The first group isalimentary infections are transmitted through soil, food, water. Digestive organs are mainly affected. Pathogens are transmitted through infected feed, soil, and manure. Such infections include anthrax, foot and mouth disease, glanders, and brucellosis.
    • The second group is  respiratory infections - damage to the mucous membranes of the respiratory tract and lungs. These include: parainfluenza, exotic pneumonia, smallpox of sheep and goats, plague of carnivores.
    • The third group is  vector-borne infections, the mechanism of their transmission is carried out using blood-sucking arthropods. These include: encephalomyelitis, tularemia, infectious anemia of horses.
    • The fourth group is  infections, the causative agents of which are transmitted through the outer integument without the participation of carriers. These include tetanus, rabies, smallpox cows.
    • Fifth group -  infections with unknown pathways of damage, i.e. unskilled group.

    Epiphytotia.  To assess the scale of plant diseases, such concepts are used epiphytotia and panfitotia.

    Epiphytotia – the spread of infectious diseases to large areas over time.

    It is known that the earth's crust, together with part of the upper mantle, is not a monolithic shell of the planet, but consists of several large blocks (plates) with a thickness of 60 to 200 km. In total, 7 huge plates and dozens of smaller plates are distinguished. The upper part of most plates is both continental and oceanic crust, that is, on these plates are continents, seas and oceans.

    The plates lie on a relatively soft, plastic layer of the upper mantle, along which they slowly move at a speed of 1 to 6 cm per year. Neighboring slabs approach, diverge or glide relative to one another. They "float" on the surface of the plastic layer of the upper mantle, like pieces of ice on the surface of the water.

    As a result of the movement of plates in the bowels of the Earth and on its surface, complex processes constantly occur. So, for example, when plates collide with the oceanic crust, deep-sea troughs (trenches) can occur, and when plates collide, which are the basis of the continental crust, mountains can form. When two plates come closer to the continental crust, their edges, together with all sedimentary rocks accumulated on them, are crumpled into folds, forming mountain ranges. With the onset of critical overloads, the folds shift and break. Breaks occur instantly, accompanied by a jolt or a series of jolts having the nature of blows. The energy released during the break is transmitted in the thickness of the earth's crust in the form of elastic seismic waves and leads to earthquakes.

    The boundary areas between lithospheric plates are called seismic belts. These are the most troubled, moving areas of the planet. Most active volcanoes are concentrated here and at least 95% of all earthquakes occur.

    Thus, geological natural phenomena are associated with the movement of lithospheric plates and changes occurring in the lithosphere.

    Geological hazard  - an event of geological origin or the result of the activity of geological processes that occur in the earth's crust under the influence of various natural or geodynamic factors or their combinations, which have or may have an impact on people, farm animals and plants, objects of the economy and the environment.

    Dangerous geological natural phenomena include earthquakes, volcanic eruptions, landslides, landslides.

    Meteorological natural phenomena

    Hazardous meteorological phenomenon  - natural processes and phenomena that occur in the atmosphere under the influence of various natural factors or their combinations, which have or may have a damaging effect on people, farm animals and plants, objects of the economy and the environment.

    These processes and phenomena are associated with various atmospheric processes, and primarily with processes occurring in the lower atmosphere — the troposphere. About 9/10 of the total mass of air is in the troposphere. Under the influence of solar heat entering the earth's surface, and the forces of gravity in the troposphere, clouds, rain, snow, and wind are formed.

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

    In the upper troposphere, on the contrary, above the equator, where ascending air flows prevail, the pressure is high, and low over the poles. Air moves all the time from the high pressure region to the low pressure region. Therefore, the air rising above the equator spreads to the poles. But due to the rotation of the Earth around its axis, moving air does not reach the poles. When cooled, it becomes heavier and falls about 30 ° north and south latitudes, forming in both hemispheres high pressure areas.

    Large volumes of tropospheric air with homogeneous properties are called air masses. Depending on the place of formation of air masses, four types are distinguished: equatorial air mass, or equatorial air; tropical air mass, or tropical air; moderate air mass, or moderate air; arctic (antarctic) air mass, or arctic (antarctic) air.

    The properties of these air masses depend on the territories over which they formed. Moving, the air masses retain their properties for a long time, and when meeting, interact with each other. The movement of air masses and their interaction determine the weather in those places where these air masses come. The interaction of various air masses leads to the formation in the troposphere of moving atmospheric vortices - cyclones and anticyclones.

    Cyclone  is a flat ascending vortex with low atmospheric pressure in the center. The diameter of the cyclone can be several thousand kilometers. The weather during the cyclone is cloudy with strong winds.

    Anticyclone  - This is a flat descending vortex with high atmospheric pressure with a maximum in the center. In the high-pressure area, air does not rise, but falls. The air spiral spins clockwise in the northern hemisphere. The weather at the anticyclone is cloudy, without precipitation, the wind is weak.

    With the movement of air masses, with their interaction, the appearance of dangerous meteorological phenomena that can cause natural disasters is associated. These are typhoons and hurricanes, storms, snow storms, tornadoes, thunderstorms, drought, severe frosts and fogs.

    Hydrological natural phenomena

    Water on the surface of the Earth is in the oceans and seas, in rivers and lakes, in the atmosphere in a gaseous state and in glaciers in a solid state.

    All waters on Earth that are not part of rocks are united by the concept of "hydrosphere". The volume of all water on Earth is so great that they measure it in cubic kilometers. A cubic kilometer is a cube with each rib size of 1 km, completely filled with water. The weight of 1 km 3 of water is equal to 1 billion tons. On the Earth contains 1.5 billion km 3 of water, 97% of them are the oceans. Currently, it is customary to divide the oceans into 4 separate oceans and 75 seas with bays and straits.

    Water is in a constant cycle, while interacting closely with the air shell of the Earth and with land.

    The driving force of the water cycle is solar energy and gravity.

    Under the influence of sunlight, water evaporates from the surface of the ocean and land (from rivers, reservoirs, soil and plants) and enters the atmosphere. Part of the water immediately returns with rains back to the ocean, part of it is carried by winds to land, where it falls to the surface in the form of rain or snow. Once in the soil, water is partially absorbed into it, replenishing the reserves of soil moisture and groundwater, and partially flows into rivers and reservoirs. Soil moisture partly passes into plants that evaporate it into the atmosphere, and partially flows into rivers. Rivers that feed on surface and groundwater carry water to the oceans, making up for its decline. Water, evaporating from the surface of the oceans, is again in the atmosphere, and the cycle is closed.

    This movement of water between the constituent parts of nature and all parts of the earth's surface has been ongoing and uninterrupted for many millions of years.

    The water cycle in nature, like a closed chain, consists of several links. Eight such links are distinguished: atmospheric, oceanic, underground, river, soil, lake, biological and economic. Water constantly moves from one link to another, linking them into a single whole. In the process of the water cycle in nature, dangerous natural phenomena constantly arise that affect the safety of human life and can lead to disastrous consequences.

    Hazardous hydrological phenomenon - an event of hydrological origin or the result of hydrological processes arising under the influence of various natural or hydrodynamic factors or their combinations, which have a striking effect on people, farm animals and plants, objects of the economy and the environment.

    Hazards of a hydrological nature include floods, tsunamis and mudflows.

    Biological Natural Hazards

    Living organisms, including humans, interact with each other and the surrounding inanimate nature. During this interaction, there is an exchange of substances and energy, there is continuous reproduction, growth of living organisms and their movement.

    Among the most dangerous natural phenomena of a biological nature that have a significant impact on human life safety, there are:

    • natural fires (forest fires, fires of steppe and grain massifs, peat fires and underground fires of fossil fuels);
    • infectious diseases of people (isolated cases of exotic and especially dangerous infectious diseases, group cases of dangerous infectious diseases, epidemic outbreak of dangerous infectious diseases, epidemic, pandemic, infectious diseases of people of unknown etiology);
    • infectious diseases of animals (single outbreaks of exotic and especially dangerous infectious diseases, enzootia, epizootics, panzootia, infectious diseases of farm animals of unknown etiology);
    • damage to agricultural plants by diseases and pests (epiphytotia, panfitotia, disease of agricultural plants of undiagnosed etiology, mass distribution of plant pests).

    Natural fires  include forest fires, fires of steppe and grain massifs, peat fires. Forest fires that occur annually are the most common, causing tremendous losses and causing fatalities.

    Forest fires are an uncontrolled burning of vegetation that spontaneously spreads through the forest territory. In dry weather and wind, forest fires cover large areas.

    In hot weather, in the absence of rain for 15-20 days, the forest becomes fire hazard. Statistics show that in 90-97% of cases, the cause of forest fires is the vital activity of people.

    Epidemic - widespread infectious disease among people, significantly exceeding the incidence rate usually recorded in a given territory. The usual (minimum) incidence for a given area is most often single cases of illness that are not related to each other.

    Epizootics  - massive infectious diseases of animals.

    Epiphytotia  - massive plant diseases.

    The massive spread of infectious diseases among people, farm animals or plants poses a direct threat to the safety of human life and can lead to emergencies.

    Infectious diseases  - This is a group of diseases that are caused by specific pathogens (bacteria, viruses, fungi). The characteristic features of infectious diseases are: infectiousness, that is, the ability to transmit pathogens from a sick organism to a healthy one; staged development (infection, incubation period, course of the disease, recovery).

    Cosmic Natural Hazards

    Earth is a cosmic body, a small particle of the Universe. Other cosmic bodies can have a profound effect on earthly life.

    Everyone saw how “falling stars” appear and go out in the night sky. it meteors  - small celestial bodies. We observe a short burst of glowing glowing gas in the atmosphere at an altitude of 70-125 km. It occurs when a meteor invades the atmosphere at high speed.

    The consequences of the fall of the Tunguska meteorite. Photo 1953

    If during the movement in the atmosphere the solid particles of the meteor do not have time to completely collapse and burn, then their remnants fall to Earth. it meteorites.

    There are also larger celestial bodies that planet Earth can meet. These are comets and asteroids.

    Comets  - These are the bodies of the solar system rapidly moving in the starry sky, moving in highly elongated orbits. As they approach the Sun, they begin to glow and they have a “head” and a “tail”. The central part of the “head” is called the core. The diameter of the core can be from 0.5 to 20 km. The core is an icy body of frozen gases and dust particles. The “tail” of a comet consists of gas molecules and dust particles that have escaped from the nucleus under the influence of sunlight. The length of the "tail" can reach tens of millions of kilometers.

    Asteroids  - These are small planets, the diameter of which varies from 1 to 1000 km.

    Currently, about 300 cosmic bodies are known that can cross the Earth’s orbit. In total, according to the forecasts of astronomers, in space there are approximately 300 thousand asteroids and comets.

    The fall of the Sikhote-Alin meteorite

    The meeting of our planet with large celestial bodies is a serious threat to the entire biosphere.

    The world of the natural environment surrounding us is constantly changing, processes of metabolism and energy are going on in it, and all this, taken together, gives rise to various natural phenomena. Depending on the intensity of manifestation and the power of the processes taking place, these natural phenomena can pose a threat to human life and an emergency situation of a natural nature.

    Check yourself

    1. What are the main groups of natural hazards.
    2. List the main natural phenomena of a geological nature and explain the reasons for their occurrence.
    3. What are the main natural phenomena of meteorological and hydrological nature you know? Indicate their interdependence.
    4. Tell us about natural hazards of a biological nature. What are the reasons for their appearance.

    After school

    Learn from adults, look on the Internet, and write in your safety diary the main natural phenomena of geological, meteorological, hydrological and biological origin in your area.

    Nature is not always as serene and beautiful as in the photograph above these lines. Sometimes she shows us her dangerous manifestations. From strong volcanic eruptions to terrifying hurricanes - it is better to contemplate the fury of nature from afar and from the side. We often underestimate the amazing and destructive power of nature, and from time to time it reminds us of this. While in photographs all this looks exciting, the consequences of such phenomena can be very scary. We must respect the power of the planet on which we live. For you, we have made this photo and video compilation of frightening natural phenomena.

    TORNADO AND OTHER TYPES OF TENDERS

    All these types of atmospheric phenomena are dangerous vortex manifestations of the elements.

    Tornado or tornado arises in a thundercloud and spreads down, often to the very surface of the earth, in the form of a cloudy sleeve or trunk tens and hundreds of meters in diameter. A tornado can appear in many shapes and sizes. Most tornadoes occur in the form of a narrow funnel (only a few hundred meters across), with a small cloud of debris near the earth's surface. A tornado can be hidden completely by a wall of rain or dust. Such tornadoes are especially dangerous, as even experienced meteorologists may not recognize them.

    Lightning tornado:


    Tornado in Oklahoma, USA (May 2010 site):

    Supercell Thunderstorm  in Montana, USA, formed by a huge rotating thundercloud 10-15 km high and dabout 50 km in diameter. Such a thunderstorm creates tornadoes, a gale, a large hail:

    Storm clouds:

    View of a hurricane tornado from space:

    There are other, apparently similar, but different in nature vortex phenomena:

    Formed as a result of the rise of warmer air from the surface of the earth. Tornado-vortices, unlike tornadoes, develop from bottom to top, and the cloud above them, if formed, is the result of the vortex, and not its cause.

    Dusty (sandy) whirlwind  - This is a vortex air movement that occurs at the surface of the earth during the day in cloudy and usually hot weather with strong heating of the earth's surface by sunlight. A whirlwind picks up dust, sand, pebbles, small objects from the surface of the earth and sometimes carries them to a site a considerable distance (hundreds of meters). Vortices pass in a narrow strip, so that with a weak wind its speed inside the vortex reaches 8-10 m / s or more.

    Sand tornado:

    Or a fire storm is formed when a column of hot, rising air interacts with the fire on the earth or becomes its cause. It is a vertical swirl of fire in the air. The air above it heats up, its density decreases, and it rises. From below, cold masses of air come from its periphery, which immediately heat up. Stable flows form, spiraling in from the earth to a height of up to 5 km. There is a chimney effect. The pressure of hot air reaches hurricane speeds. The temperature rises to 1000˚С. Everything burns or melts. Moreover, everything that is nearby is "absorbed" into the fire. And so on until all that can burn is burned.

    The site is a funnel-shaped air-water vortex, similar in nature to the usual tornado, formed above the surface of a large body of water and connected to a cumulus cloud. A water tornado can form if a normal tornado passes over a water surface. Unlike the classic tornado, a water tornado exists only 15-30 minutes, is much smaller in diameter, the speed of movement and rotation is two to three times lower, it is not always accompanied by a hurricane wind.

    DUSTY OR SANDSTORM

    Sandstorm  - This is a dangerous atmospheric phenomenon, which manifests itself in the form of wind transfer of a large number of soil particles, dust or small grains of sand from the surface of the Earth. The height of the layer of such dust can be several meters, while horizontal visibility deteriorates noticeably. For example, at a level of 2 meters, visibility is 1-8 kilometers, but often the view in the storm is reduced to several hundred and even tens of meters. Dust storms occur site mainly with dry soil surface and wind speed of more than 10 meters per second.

    That the storm is approaching, you can understand in advance by the incredible silence that forms around, as if you suddenly fell into a vacuum. This silence is oppressive, creating inexplicable anxiety within you.

    Sandstorm on the streets of Onslow in northwest Australia, January 2013:

    Sandstorm in Golmud Village, Qinghai Province, China, 2010:

    Red sandstorm in Australia:

    TSUNAMI

      - This is a dangerous natural disaster, which is sea waves resulting from a shift of the seabed during underwater and coastal earthquakes. Formed in any place, a tsunami can spread at high speed (up to 1000 km / h) over several thousand kilometers, while the height of the tsunami is initially from 0.1 to 5 meters. Upon reaching shallow water, the wave height increases sharply, reaching a height of 10 to a site of 50 meters. Huge masses of water discharged ashore lead to flooding and destruction of the area, as well as to the death of people and animals. An air shock wave propagates in front of the water shaft. It acts like a blast wave, destroying buildings and structures. The tsunami wave may not be the only one. Very often, this is a series of waves that rolls ashore with an interval of 1 hour or more.

    Tsunami in Thailand caused by an earthquake (9.3 points) in the Indian Ocean on December 26, 2004:

    CATASTROPHIC FLOOD

    Flood - flooding of the territory with water, which is a natural disaster. Floods come in many forms and are caused by various causes. Catastrophic floods lead to loss of life, irreparable environmental damage, cause material damage, covering vast territories within one or more water systems. At the same time, the economic site and production activities are completely paralyzed, the lifestyle of the population is temporarily changing. The evacuation of hundreds of thousands of the population, the inevitable humanitarian catastrophe requires the participation of the entire world community, the problem of one country becomes the problem of the whole world.

    Flooding in Khabarovsk and the Khabarovsk Territorycaused by heavy rains covering the entire Amur River basin and lasting about two months (2013):

    Flooding New Orleans after a hurricane.New Orleans (USA) stands on wet ground, which is not able to support the city. Orleans plunges slowly into the earth, and the Gulf of Mexico gradually rises around it. Most of New Orleans is already 1.5 to 3 meters below sea level. Hurricane Katrina contributed to this to a large extent in 2005:

    Flooding in Germany, in the Rhine basin (2013):

    Flood in Iowa, USA (2008):

    THunderstorm Lightning

    Lightning discharges (lightning)  They represent a gigantic electric spark discharge in the site of the atmosphere, with a very long spark, usually occurs during a thunderstorm, manifested by a bright flash of light and the accompanying thunder. The total length of the lightning channel reaches several kilometers (2.5 km on average), and a significant part of this channel is located inside a thundercloud. Some discharges extend in the atmosphere up to a distance of 20 km. The current in the lightning discharge reaches 10-20 thousand amperes, so not all people survive after a lightning strike.

    Forest fire  - This is a spontaneous, uncontrolled spread of fire in forest areas. The causes of fires in the forest can be natural (lightning, drought, etc.) and artificial when people are the cause. Forest fires come in several forms.

    Underground (soil) fires  in the forest are most often associated with the ignition of peat, which becomes possible as a result of drainage of swamps. They can be inconspicuous and extend to a depth of up to a site of several meters, as a result of which they pose an additional danger and are extremely difficult to extinguish. As, for example, a peat fire in the suburbs (2011):

    At ground fire forest litter, lichens, mosses, grasses, branches fallen on the ground burn down, etc.

    Horse forest fire  covers leaves, needles, branches and the entire crown; it can cover (in case of a wildfire) grass-moss cover of soil and undergrowth. They usually develop in dry, windy weather from a ground fire, in stands with low crowned crowns, in stands of different ages, as well as in abundant coniferous undergrowth. This is usually the final stage of a fire.

    Volcanoes

    Volcanoes  - These are geological formations on the surface of the earth's crust, most often in the form of a mountain, where magma comes to the surface, forming lava, volcanic gases, stones and pyroclastic flows. When molten magma spills through cracks in the earth's crust, a volcano erupts, a site named after the Roman god of fire and blacksmithing.

    Karymsky Volcano is one of the most active volcanoes in Kamchatka:

    Underwater volcano - coast of the Tonga archipelago (2009):

    Submarine volcano and subsequent tsunami:

    Eruption of a volcano photographed from space:

    Klyuchevskoi Volcano in Kamchatka (1994):

    The eruption of Sinabung volcano in Sumatra was accompanied by several mini-tornadoes:

    Eruption of the Puyeue volcano in Chile:

    Lightning in the ash cloud of Chaiten volcano in Chile:

    Volcanic lightning:

    EARTHQUAKES

    Earthquake  - These are tremors and vibrations of the Earth's surface caused by natural tectonic processes (movement of the earth's crust and displacements and gaps occurring in it) or artificial processes (explosions, filling reservoirs, collapse of underground cavities of mine workings). May cause eruptions of volcanoes and tsunamis.

    Japan earthquake followed by tsunami (2011):

    LANDSLIDE

    Landslide  - the separated mass of loose rocks, slowly and gradually crawling in a stepwise or irregular manner along the inclined separation plane, while often maintaining its cohesion, solidity and without overturning its soil.

    SEL

    Sel  - a stream with a very high concentration of mineral particles, stones and rock fragments (a cross between liquid and solid mass) that suddenly appears in the basins of small mountain rivers and is caused, as a rule, by heavy rainfall or violent snowmelt.

    SNOW AVALANCHES

    Snow avalanches  relate to landslides. This is a mass of snow falling or slipping from the slopes of the mountains.

    This is one of record avalanches  the size of 600 thousand cubic meters. The film crew was not affected:

    “This is the consequence of an avalanche - snow dust, it flew high, and everything disappeared like in a fog. Everyone was covered with snow dust, which by inertia continued to move at the speed of a snowstorm. It was dark like at night. Because of the fine, fine snow it was difficult for the site to breathe. Arms and legs instantly froze. I have not seen anyone around. Although there were people nearby, ”said Anton Wojciechowski, a member of the crew.

    Dangerous natural phenomena mean extreme climatic or meteorological phenomena occurring naturally in one way or another point on the planet. In some regions, such dangerous phenomena can occur with a greater frequency and destructive force than in others. Natural hazards develop into natural disasters when the infrastructure created by civilization is destroyed and people themselves die.

    1. Earthquakes

    Among all natural hazards, the first place should be given to earthquakes. In places of ruptures of the earth's crust, tremors occur, which cause oscillations of the earth's surface with the release of gigantic energy. The arising seismic waves are transmitted over very large distances, although these waves have the greatest destructive force in the epicenter of an earthquake. Due to strong fluctuations in the earth's surface, massive destruction of buildings occurs.
    Since there are quite a lot of earthquakes, and the earth’s surface is quite densely built up, the total number of people in history who died precisely as a result of earthquakes exceeds the number of all victims of other natural disasters and amounts to many millions. For example, over the past decade, around 700 thousand people have died from earthquakes around the world. From the most destructive tremors, entire settlements collapsed instantly. Japan is the country most affected by earthquakes, and one of the most catastrophic earthquakes occurred there in 2011. The epicenter of this earthquake was in the ocean near the island of Honshu, on the Richter scale, the shock force reached 9.1 points. Powerful shocks and the ensuing devastating tsunami destroyed the Fukushima nuclear power plant, destroying three out of four power units. Radiation covered a significant area around the station, making dense populated areas unsuitable for life, so valuable in Japan. Of tremendous power, the tsunami wave turned into a mess that could not destroy the earthquake. Only officially died over 16 thousand people, to which you can safely reckon another 2.5 thousand, considered missing. Only in this century, devastating earthquakes occurred in the Indian Ocean, Iran, Chile, Haiti, Italy, Nepal.

    2. Tsunami waves

    A specific water disaster in the form of tsunami waves often results in numerous casualties and catastrophic destruction. As a result of underwater earthquakes or shifts of tectonic plates, very fast but subtle waves appear in the ocean, which grow into huge waves as they approach the shores and go into shallow water. Most often, tsunamis occur in areas with increased seismic activity. A huge mass of water, rapidly approaching the shore, blows everything in its path, picks it up and carries it deeper into the coast, and then carries it back to the ocean with a reverse current. People who are unable to feel danger, like animals, often do not notice the approach of a death wave, and when they notice, it becomes too late.
    More people are usually killed by the tsunami than by the earthquake that caused it (the last case in Japan). In 1971, the most powerful tsunami observed occurred there, the wave of which rose 85 meters at a speed of about 700 km / h. But the most catastrophic was the tsunami observed in the Indian Ocean (the source is an earthquake off the coast of Indonesia), which claimed the lives of about 300 thousand people along a significant part of the Indian Ocean.


       Tornado (in America this phenomenon is called a tornado) is a fairly stable atmospheric vortex, most often occurring in thunderclouds. He is a visa ...

    3. Volcano eruption

    Throughout its history, mankind has remembered many catastrophic volcanic eruptions. When the pressure of magma exceeds the strength of the earth's crust in the weakest places, which are volcanoes, it ends with an explosion and outpourings of lava. But the lava itself is not so dangerous, from which one can simply get away, like hot pyroclastic gases rushing from the mountain, pierced here and there by lightning, as well as a noticeable effect on the climate of the strongest eruptions.
      Volcanologists count with five hundred dangerous active volcanoes, several sleeping supervolcanoes, not counting thousands of extinct. So, during the eruption of the Tambora volcano in Indonesia for two days, the surrounding lands were plunged into darkness, 92 thousand inhabitants died, and even the cooling in Europe and America was felt.
      List of some strong volcanic eruptions:

    • Volcano Lucky (Iceland, 1783). As a result of that eruption, a third of the island’s population died - 20 thousand inhabitants. The eruption lasted for 8 months, during which flows of lava and liquid mud erupted from volcanic cracks. Geysers have become more active than ever. Living on the island at that time was almost impossible. The crop was destroyed, and even the fish disappeared, so the survivors experienced hunger and suffered from unbearable living conditions. Perhaps this is the longest eruption in human history.
    • Tambora Volcano (Indonesia, Sumbawa Island, 1815). When the volcano exploded, the sound of this explosion spread over 2 thousand kilometers. Even the remote islands of the archipelago covered with ashes, 70 thousand people died from the eruption. But even today, Tambora is one of the highest mountains in Indonesia, which maintains volcanic activity.
    • Volcano Krakatau (Indonesia, 1883). 100 years after Tambora, another catastrophic eruption occurred in Indonesia, this time "demolished" (literally) the volcano Krakatau. After a catastrophic explosion that destroyed the volcano itself, terrifying peals were heard for another two months. A gigantic amount of rocks, ash and hot gases were thrown into the atmosphere. The eruption was followed by a powerful tsunami with a wave height of up to 40 meters. These two natural disasters together destroyed 34 thousand islanders along with the island itself.
    • Volcano Santa Maria (Guatemala, 1902). After a 500-year hibernation in 1902, this volcano woke up again, beginning the 20th century with the most catastrophic eruption, which resulted in the formation of a 1.5 km long crater. In 1922, Santa Maria again reminded herself - this time the eruption itself was not too strong, but a cloud of hot gases and ash caused the death of 5 thousand people.

    4. Tornadoes


       Throughout the history of mankind, the strongest earthquakes have done tremendous damage to people more than once and caused a huge number of victims among the population ...

    A tornado is a very impressive natural phenomenon, especially in the USA, where it is called a tornado. This is an air stream spiraling into a funnel. Small tornadoes resemble slender narrow pillars, and giant tornadoes can resemble a powerful carousel directed towards the sky. The closer to the funnel, the stronger the wind speed, it begins to entrain more and more large objects, including cars, wagons and light buildings. In the "tornado alley" of the United States, whole city blocks are often destroyed and people die. The most powerful vortexes of the F5 category reach a speed of about 500 km / h in the center. Alabama tornado suffers the most each year.

    There is a kind of fire tornado, which sometimes occurs in the area of \u200b\u200bmass fires. There, from the heat of the flame, powerful updrafts form, which begin to twist into a spiral, like an ordinary tornado, only this one is filled with flame. As a result, a powerful traction is formed near the surface of the earth, from which the flame grows even more and burns everything around. When a catastrophic earthquake occurred in Tokyo in 1923, it caused massive fires, which led to the formation of a fiery tornado that rose 60 meters. The pillar of fire moved towards the square with frightened people and burned 38 thousand people in a few minutes.

    5. Sandstorms

    This phenomenon occurs in sandy deserts when a strong wind rises. Sand, dust and particles of soil rise to a sufficiently high height, forming a cloud that dramatically reduces visibility. If an unprepared traveler gets into such a storm, then he may die from grains of sand falling into the lungs. Herodotus described the story as 525 BC. e. in the Sahara, a 50,000th army was buried alive by a sandstorm. In Mongolia, in 2008, 46 people died as a result of this natural phenomenon, and a year earlier, two hundred people suffered the same fate.


       Occasionally, tsunami waves occur in the ocean. They are very insidious - in the open ocean they are completely invisible, but if they get closer to the coastal shelf, g ...

    6. Avalanches

    Snow avalanches periodically leave snow-capped mountain peaks. Climbers especially often suffer from them. During the First World War, up to 80 thousand people died from avalanches in the Tyrolean Alps. In 1679, five hundred people died from snow in Norway. In 1886 there was a major disaster, as a result of which the “white death" claimed 161 lives. The records of Bulgarian monasteries also mention the human victims of avalanches.

    7. Hurricanes

    In the Atlantic, they are called hurricanes, and in the Pacific, typhoons. These are huge atmospheric vortices, in the center of which the strongest winds and sharply reduced pressure are observed. A few years ago, the devastating Hurricane Katrin swept over the United States, which particularly affected Louisiana and the densely populated New Orleans located at the mouth of the Mississippi. 80% of the city were flooded, killing 1836 people. Famous destructive hurricanes also became:

    • Hurricane Ike (2008). The diameter of the vortex was over 900 km, and in the center of its vortex the wind blew at a speed of 135 km / h. In the 14 hours that the cyclone moved across the United States, he managed to inflict damage on $ 30 billion.
    • Hurricane Wilma (2005). This is the largest Atlantic cyclone in the history of meteorological observations. The cyclone that originated in the Atlantic several times went on land. The amount of damage caused by him amounted to $ 20 billion, killing 62 people.
    • Typhoon Nina (1975). This typhoon was able to break through the Chinese Banqiao dam, which led to the destruction of the dams below and a catastrophic flood. From the typhoon killed up to 230 thousand Chinese.

    8. Tropical cyclones

    These are the same hurricanes, but in tropical and subtropical waters, which are huge atmospheric low-pressure systems with winds and thunderstorms, in diameter often exceeding a thousand kilometers. Near the surface of the earth, winds in the center of the cyclone can reach speeds of more than 200 km / h. Low pressure and wind cause the formation of a coastal storm surge - when enormous masses of water are thrown onto the shore at high speed, washing away everything in its path.


       Environmental disasters have their own specifics - during them not a single person may die, but a very significant one will be inflicted ...

    9. Landslide

    Long rains can cause landslides. The soil swells, loses stability and slides down, carrying with it everything that is on the surface of the earth. Most often, landslides occur in the mountains. In 1920, the most destructive landslide occurred in China, under which 180 thousand people were buried. Other examples:

    • Bududa (Uganda, 2010). Due to mudflows, 400 people died, and 200 thousand had to be evacuated.
    • Sichuan (China, 2008). Avalanches, landslides and mudflows caused by an 8-point earthquake, claimed 20 thousand lives.
    • Leite (Philippines, 2006). Rainfall caused mudflows and a landslide, which killed 1,100 people.
    • Vargas (Venezuela, 1999). Mudflows and landslides after heavy rains (almost 1000 mm of precipitation fell in 3 days) on the northern coast led to the death of almost 30 thousand people.

    10. Ball lightnings

    We are accustomed to the usual linear lightning accompanied by thunder, but ball lightning is much more rare and mysterious. The nature of this phenomenon is electric, but scientists cannot yet give a more accurate description of ball lightning. It is known that it can have different sizes and shapes, most often it is yellowish or reddish luminous spheres. For unknown reasons, ball lightning often ignores the laws of mechanics. Most often they occur before a thunderstorm, although they can appear in absolutely clear weather, as well as indoors or in the cockpit. A luminous ball with a slight hissing hangs in the air, then it can begin to move in an arbitrary direction. Over time, it seems to shrink, until it completely disappears or explodes with a roar. But the damage to ball lightning can be very limited.