Natural emergency situations, depending on the type, scale and consequences, are conventionally divided into natural disasters(large in scale and with severe consequences) and dangerous natural phenomena.
IN Lately More hazardous phenomena lead to serious consequences and are regarded as emergency situations. For example, frost and icing at the beginning of the last century did not cause serious harm, while in the winter of 2001 several regions of Ukraine were left without electricity, which, of course, caused enormous material and economic damage.
Natural disasters- these are dangerous processes of lithospheric, atmospheric, hydrological, biosphere or other origin of such a scale that lead to catastrophic situations with sudden disturbances systems of life activity of the population, destruction and destruction of material assets, objects of the national economy
Types of natural disasters:
- Meteorological:
o significant increase or decrease in temperature.
- Tectonic:
o earthquake,
o volcanic eruption,
- Topological:
o flood,
o mudflow,
o rockfall,
o snow drifts,
- Space:
o increased radioactive radiation,
o the fall of a large cosmic body.
- Biological:
o abnormal increase in the number of macrobiological objects,
o diseases and damage to plants and animals,
o epidemic.
Hazardous natural phenomena - These are processes that can lead to negative consequences in a small area and become causes of emergencies of natural or man-made origin.
Types of hazardous natural phenomena:
o lightning strike,
o black ice
o strong wind.
Global natural, and in some cases man-made, emergency situations, the environmental consequences of which extend to the entire or most of the planet, are called disasters.
The consequences of some of the largest natural disasters that occurred on Earth are shown in Table 2.2.
Table 2.2
The largest natural disasters and the number of their victims
|
Type of disaster |
Description and number of victims |
Possible number of victims in a disaster of the same scale in modern conditions |
|
River floods |
In June 1931, there was a flood on the river. Huang-se in China. The number of victims is from 1 to 2 million people. |
2-3 million people |
|
Earthquakes |
On January 24, 1556, a strong earthquake in China (Shaanxi province) killed 830 thousand people. |
1.0 - 1.5 million people |
|
Eruption<я вулка-нов |
The eruption of Mount Etna in 1669 destroyed the town of Catania and other settlements. 100 thousand people died. |
1 - 2 million people |
|
Typhoons |
0.5 - 1.0 million people |
|
|
Tsunami |
On August 27, 1883, a tsunami resulting from the eruption of the Krakatoa volcano led to the death of 36.4 thousand people. |
100 - 200 thousand people |
|
Landslides |
0.5 million people |
All natural hazards are characterized general principles:
Each type of hazard is preceded by some specific signs;
Despite the unexpected nature of a natural hazard, its occurrence can be foreseen;
The greater the intensity of a dangerous phenomenon, the less often it occurs;
Each type of hazard is characterized by a certain spatial conditionality;
To prevent natural emergencies, passive and active protective measures can be used. Active protection from natural hazards involves the construction of engineering structures, intervention in the mechanism of the phenomenon, reconstruction of natural objects, etc., passive - the use of protective structures. In most cases, passive and active protection methods are combined.
The Earth is fraught with many unusual and sometimes inexplicable phenomena, and from time to time all sorts of phenomena and even cataclysms occur throughout the globe, most of which can hardly be called ordinary and familiar to humans. Some cases have completely understandable reasons, but there are also those that even experienced scientists have not been able to explain for many decades. True, this kind of natural disasters do not happen often, only a few times during the year, but, nevertheless, humanity’s fear of them does not disappear, but, on the contrary, grows.
The most dangerous natural phenomena
These include the following types of disasters:
Earthquakes
This is a dangerous natural phenomenon in the ranking of the most dangerous natural anomalies. Tremors of the earth's surface, occurring in places where the earth's crust breaks, provoke vibrations that turn into seismic waves of significant power. They are transmitted over considerable distances, but become strongest near the immediate source of tremors and provoke large-scale destruction of houses and buildings. Since there are a huge number of buildings on the planet, the number of victims runs into the millions. Over all time, earthquakes have affected many more people in the world than other disasters. Over the past ten years alone, more than seven hundred thousand people have died from them in different countries of the world. Sometimes the tremors reached such strength that entire settlements were destroyed in an instant.
Tsunami waves
Tsunamis are natural disasters that cause a lot of destruction and death. Waves of enormous height and strength that arise in the ocean, or in other words, tsunamis, are a consequence of earthquakes. These giant waves usually occur in areas where seismic activity is significantly increased. The tsunami moves very quickly, and once it gets aground, it begins to rapidly grow in length. Once this huge fast wave reaches the shore, it can destroy everything in its path in a matter of minutes. The destruction caused by a tsunami is usually large-scale, and people who are caught by surprise by the cataclysm often do not have time to escape.
Ball lightning
Lightning and thunder are common things, but a type such as ball lightning is one of the most terrible natural phenomena. Ball lightning is a powerful electric discharge of current, and it can take on absolutely any shape. Typically, this type of lightning looks like balls of light, most often reddish or yellow in color. It is curious that these lightning completely ignore all the laws of mechanics, appearing out of nowhere, usually before a thunderstorm, inside houses, on the street or even in the cockpit of an airplane that is flying. Ball lightning hovers in the air, and does so very unpredictably: for a few moments, then it becomes smaller, and then disappears completely. It is strictly forbidden to touch ball lightning; moving when encountering it is also undesirable.
Tornadoes
This natural anomaly is also one of the most terrible natural phenomena. Typically, a tornado is an air flow that twists into a kind of funnel. Outwardly, it looks like a columnar, cone-shaped cloud, inside of which air moves in a circle. All objects that fall into the tornado zone also begin to move. The speed of air flow inside this funnel is so enormous that it can easily lift very heavy objects weighing several tons and even houses into the air.
Sandstorms
This type of storm occurs in deserts due to strong winds. Dust and sand, and sometimes soil particles carried by the wind, can reach several meters in height, and in the area where the storm breaks out, there will be a sharp decrease in visibility. Travelers caught in such a storm risk death because sand gets into their lungs and eyes.
Bloody Rains
This unusual natural phenomenon owes its threatening name to a strong waterspout, which sucked out particles of red algae spores from the water in reservoirs. When they mix with the water masses of a tornado, the rain takes on a terrible red hue, very reminiscent of blood. This anomaly was observed by residents of India for several weeks in a row; rain the color of human blood caused fear and panic among people.
Fire tornadoes
Natural phenomena and disasters are most often unpredictable. These include one of the most terrible - a fire tornado. This type of tornado is already dangerous, but , if it occurs in a fire zone, it should be even more feared. Near several fires, when a strong wind occurs, the air above the fires begins to warm up, its density becomes less, and it begins to rise upward along with the fire. In this case, the air flows twist into peculiar spirals, and the air pressure acquires enormous speed.
The fact that the most terrible natural phenomena are poorly predicted. They often come suddenly, taking people and authorities by surprise. Scientists are working to create advanced technologies that can predict upcoming events. Today, the only guaranteed way to avoid the “vagaries” of the weather is to move to areas where such phenomena are observed as rarely as possible or have not been recorded before.
What are natural phenomena? What are they? You will find answers to these questions in this article. The material can be useful both for preparing for a lesson on the world around us and for general development.
Everything that surrounds us and is not created by human hands is nature.
All changes that occur in nature are called natural phenomena or natural phenomena. The rotation of the Earth, its movement in orbit, the change of day and night, the change of seasons are examples of natural phenomena.
Seasons are also called seasons. Therefore, natural phenomena associated with the changing seasons are called seasonal phenomena.
Nature, as you know, can be inanimate and living.
Inanimate nature includes: the Sun, stars, celestial bodies, air, water, clouds, stones, minerals, soil, precipitation, mountains.
Living nature includes plants (trees), mushrooms, animals (animals, fish, birds, insects), microbes, bacteria, and humans.
In this article we will look at winter, spring, summer and autumn natural phenomena in animate and inanimate nature.
Winter natural phenomena
| Examples of winter phenomena in inanimate nature | Examples of winter phenomena in wildlife |
|---|---|
|
|
Spring natural phenomena
| Names of spring phenomena in inanimate nature | Names of spring phenomena in wildlife |
|---|---|
|
|
Summer natural phenomena
| Summer natural phenomena in inanimate nature | Summer natural phenomena in wildlife |
|---|---|
|
|
Autumn natural phenomena
| Autumn phenomena in inanimate nature | Autumn phenomena in wildlife |
|
|
Unusual natural phenomena
What natural phenomena still exist? In addition to the seasonal natural phenomena described above, there are several more that are not associated with any time of year.
- Flood called a short-term sudden rise in water level in a river. This sharp rise may be a consequence of heavy rains, the melting of large amounts of snow, the release of an impressive volume of water from the reservoir, or the collapse of glaciers.
- Northern lights- glow of the upper layers of the atmospheres of planets with a magnetosphere due to their interaction with charged particles of the solar wind.
- Ball lightning- a rare natural phenomenon that looks like a luminous formation floating in the air.
- Mirage- an optical phenomenon in the atmosphere: refraction of light streams at the boundary between layers of air that are sharply different in density and temperature.
- « Falling star" - an atmospheric phenomenon that occurs when meteoroids enter the Earth's atmosphere
- Hurricane- extremely fast and strong air movement, often of great destructive power and considerable duration
- Tornado- an ascending vortex of extremely quickly rotating air in the form of a funnel of enormous destructive power, in which moisture, sand and other suspended matter are present.
- Ebbs and flows- These are changes in the water level of the sea elements and the World Ocean.
- Tsunami- long and high waves generated by a powerful impact on the entire thickness of water in the ocean or other body of water.
- Earthquake- represent tremors and vibrations of the earth's surface. The most dangerous of them arise due to tectonic displacements and ruptures in the earth's crust or upper mantle of the Earth
- Tornado- an atmospheric vortex that arises in a cumulonimbus (thunderstorm) cloud and spreads down, often to the very surface of the earth, in the form of a cloud arm or trunk with a diameter of tens and hundreds of meters
- Eruption- the process of a volcano throwing hot debris, ash onto the earth's surface, an outpouring of magma, which, pouring onto the surface, becomes lava.
- Floods- flooding of land with water, which is a natural disaster.
Over the billions of years of our planet’s existence, certain mechanisms by which nature works have formed. Many of these mechanisms are subtle and harmless, while others are large-scale and cause enormous destruction. In this rating, we will talk about the 11 most destructive natural disasters on our planet, some of which can destroy thousands of people and an entire city in a few minutes.
11
A mudflow is a mud or mud-stone flow that suddenly forms in the beds of mountain rivers as a result of rainfall, rapid melting of glaciers or seasonal snow cover. The decisive factor in the occurrence may be deforestation in mountainous areas - tree roots hold the top of the soil, which prevents the occurrence of a mudflow. This phenomenon is short-term and usually lasts from 1 to 3 hours, typical for small watercourses up to 25-30 kilometers long. Along their path, streams carve deep channels that are usually dry or contain small streams. The consequences of mudflows can be catastrophic.
Imagine that a mass of earth, silt, stones, snow, sand, driven by a strong flow of water, fell on the city from the mountains. This stream will demolish the dacha buildings located at the foot of the city along with people and orchards. This entire stream will rush into the city, turning its streets into raging rivers with steep banks of destroyed houses. Houses will be torn off their foundations and, along with their people, will be carried away by a stormy stream.
10
Landslide is the sliding of masses of rocks down a slope under the influence of gravity, often while maintaining their coherence and solidity. Landslides occur on the slopes of valleys or river banks, in the mountains, on the shores of the seas, and the largest ones occur at the bottom of the seas. The displacement of large masses of earth or rock along a slope is caused in most cases by wetting the soil with rainwater so that the soil mass becomes heavier and more mobile. Such large landslides damage agricultural lands, enterprises, and populated areas. To combat landslides, bank protection structures and planting of vegetation are used.
Only rapid landslides, the speed of which is several tens of kilometers, can cause real natural disasters with hundreds of casualties when there is no time for evacuation. Imagine that huge pieces of soil are quickly moving from a mountain directly onto a village or city, and under tons of this earth, buildings are destroyed and people who did not have time to leave the landslide site die.
9
A sandstorm is an atmospheric phenomenon in which large quantities of dust, soil particles and grains of sand are transported by the wind several meters from the ground with a noticeable deterioration in horizontal visibility. In this case, dust and sand rise into the air and at the same time dust settles over a large area. Depending on the color of the soil in a given region, distant objects take on a grayish, yellowish or reddish tint. It usually occurs when the soil surface is dry and the wind speed is 10 m/s or more.
Most often, these catastrophic phenomena occur in the desert. A sure sign that a sandstorm is starting is sudden silence. Rustles and sounds disappear with the wind. The desert literally freezes. A small cloud appears on the horizon, which quickly grows and turns into a black and purple cloud. The missing wind rises and very quickly reaches speeds of up to 150-200 km/h. A sandstorm can cover streets within a radius of several kilometers with sand and dust, but the main danger of sandstorms is the wind and poor visibility, which causes car accidents in which dozens of people are injured and some even die.
8
An avalanche is a mass of snow falling or sliding down the slopes of mountains. Snow avalanches pose a significant danger, causing casualties among climbers, skiers and snowboarders and causing significant damage to property. Sometimes avalanches have catastrophic consequences, destroying entire villages and causing the death of dozens of people. Snow avalanches, to one degree or another, are common in all mountainous regions. In winter, they are the main natural danger of the mountains.
Tones of snow are held on top of mountains due to the force of friction. Large avalanches occur at the moment when the pressure force of the snow mass begins to exceed the force of friction. A snow avalanche is usually triggered by climatic reasons: sudden changes in weather, rain, heavy snowfalls, as well as mechanical effects on the snow mass, including the effects of rockfalls, earthquakes, etc. Sometimes an avalanche can begin due to a minor shock such as a weapon shot or pressure on the snow of a person. The volume of snow in an avalanche can reach several million cubic meters. However, even avalanches with a volume of about 5 m³ can be life-threatening.
7
A volcanic eruption is the process of a volcano throwing hot debris, ash, and magma onto the earth’s surface, which, when poured onto the surface, becomes lava. A major volcanic eruption can last from a few hours to many years. Hot clouds of ash and gases, capable of moving at speeds of hundreds of kilometers per hour and rising hundreds of meters into the air. The volcano emits gases, liquids and solids with high temperatures. This often causes the destruction of buildings and loss of life. Lava and other hot erupted substances flow down the slopes of the mountain and burn out everything they meet on their way, causing innumerable casualties and staggering material losses. The only protection against volcanoes is general evacuation, so the population must be familiar with the evacuation plan and unquestioningly obey the authorities if necessary.
It is worth noting that the danger from a volcanic eruption exists not only for the region around the mountain. Potentially, volcanoes threaten the lives of all life on Earth, so you shouldn’t be lenient towards these hot guys. Almost all manifestations of volcanic activity are dangerous. The danger of boiling lava goes without saying. But no less terrible is the ash, which penetrates literally everywhere in the form of continuous gray-black snowfall, which covers streets, ponds, and entire cities. Geophysicists say they are capable of eruptions hundreds of times more powerful than those ever observed. Major volcanic eruptions, however, have already occurred on Earth - long before the advent of civilization.
6
A tornado or tornado is an atmospheric vortex that arises in a thundercloud and spreads down, often to the very surface of the earth, in the form of a cloud arm or trunk with a diameter of tens and hundreds of meters. Typically, the diameter of a tornado funnel on land is 300-400 meters, but if a tornado occurs on the surface of water, this value can be only 20-30 meters, and when the funnel passes over land it can reach 1-3 kilometers. The largest number of tornadoes is recorded on the North American continent, especially in the central states of the United States. About a thousand tornadoes occur in the United States every year. The strongest tornadoes can last up to an hour or more. But most of them last no more than ten minutes.
On average, about 60 people die from tornadoes each year, mostly from flying or falling debris. However, it happens that huge tornadoes rush at a speed of about 100 kilometers per hour, destroying all buildings in their path. The maximum recorded wind speed in the largest tornado is about 500 kilometers per hour. During such tornadoes, the death toll can number in the hundreds and the number of injured in the thousands, not to mention the material damage. The reasons for the formation of tornadoes have not yet been fully studied.
5
A hurricane or tropical cyclone is a type of low-pressure weather system that occurs over a warm sea surface and is accompanied by severe thunderstorms, heavy rainfall and gale-force winds. The term “tropical” refers to both the geographic area and the formation of these cyclones in tropical air masses. It is generally accepted, according to the Beaufort scale, that a storm becomes a hurricane when wind speeds exceed 117 km/h. The strongest hurricanes can cause not only extreme downpours, but also large waves on the sea surface, storm surges and tornadoes. Tropical cyclones can arise and maintain their strength only over the surface of large bodies of water, while over land they quickly lose strength.
A hurricane can cause heavy rain, tornadoes, small tsunamis and floods. The direct effect of tropical cyclones on land is stormy winds that can destroy buildings, bridges and other man-made structures. The strongest sustained winds within the cyclone exceed 70 meters per second. The worst effect of tropical cyclones in terms of death toll has historically been storm surge, the rise in sea level caused by the cyclone, which on average accounts for about 90% of the casualties. Over the past two centuries, tropical cyclones have killed 1.9 million people worldwide. In addition to the direct effect on residential buildings and economic facilities, tropical cyclones destroy infrastructure, including roads, bridges, and power lines, causing enormous economic damage to the affected areas.
The most destructive and terrible hurricane in US history, Katrina, occurred at the end of August 2005. The heaviest damage was caused to New Orleans in Louisiana, where about 80% of the city's area was under water. The disaster killed 1,836 residents and caused economic losses of $125 billion.
4
Flood - flooding of an area as a result of rising water levels in rivers, lakes, seas due to rain, rapid snow melting, wind surge of water to the coast and other reasons, which damages people's health and even leads to their death, and also causes material damage . For example, in mid-January 2009, the largest flood in Brazil occurred. More than 60 cities were affected then. About 13 thousand people fled their homes, more than 800 people died. Floods and numerous landslides are caused by heavy rains.
Heavy monsoon rains have continued in Southeast Asia since mid-July 2001, causing landslides and flooding in the Mekong River region. As a result, Thailand experienced its worst floods in the last half century. Streams of water flooded villages, ancient temples, farms and factories. At least 280 people died in Thailand, and another 200 in neighboring Cambodia. Some 8.2 million people in 60 of Thailand's 77 provinces have been affected by the floods, and economic losses so far are estimated to exceed $2 billion.
Drought is a long period of stable weather with high air temperatures and low precipitation, as a result of which the soil moisture reserves decrease and the suppression and death of crops occurs. The onset of severe drought is usually associated with the establishment of a sedentary high anticyclone. The abundance of solar heat and gradually decreasing air humidity create increased evaporation, and therefore the reserves of soil moisture are depleted without replenishment by rain. Gradually, as soil drought intensifies, ponds, rivers, lakes, and springs dry up—a hydrological drought begins.
For example, in Thailand, almost every year, severe floods alternate with severe droughts, when a state of emergency is declared in dozens of provinces, and several million people feel the effects of the drought in one way or another. As for the victims of this natural phenomenon, in Africa alone, from 1970 to 2010, the death toll from droughts is 1 million people.
2
Tsunamis are long waves generated by a powerful impact on the entire thickness of water in the ocean or other body of water. Most tsunamis are caused by underwater earthquakes, during which a portion of the seabed suddenly shifts. Tsunamis are formed during an earthquake of any strength, but those that arise due to strong earthquakes with a magnitude of more than 7 on the Richter scale reach great strength. As a result of an earthquake, several waves are propagated. More than 80% of tsunamis occur on the periphery of the Pacific Ocean. The first scientific description of the phenomenon was given by José de Acosta in 1586 in Lima, Peru, after a powerful earthquake, then a strong tsunami 25 meters high burst onto land at a distance of 10 km.
The largest tsunamis in the world occurred in 2004 and 2011. So, on December 26, 2004 at 00:58, a powerful earthquake of magnitude 9.3 occurred - the second most powerful of all recorded, which caused the deadliest tsunami of all known. Asian countries and African Somalia were hit by the tsunami. The total number of deaths exceeded 235 thousand people. The second tsunami occurred on March 11, 2011 in Japan after a strong earthquake of magnitude 9.0 with an epicenter caused a tsunami with a wave height exceeding 40 meters. In addition, the earthquake and subsequent tsunami caused the accident at the Fukushima I nuclear power plant. As of July 2, 2011, the official death toll from the earthquake and tsunami in Japan is 15,524 people, 7,130 people are missing, 5,393 people wounded.
1
An earthquake is an underground tremors and vibrations of the Earth's surface caused by natural causes. Small tremors can also be caused by the rise of lava during volcanic eruptions. About a million earthquakes occur throughout the Earth each year, but most are so small that they go unnoticed. The strongest earthquakes, capable of causing widespread destruction, occur on the planet approximately once every two weeks. Most of them fall on the bottom of the oceans, and therefore are not accompanied by catastrophic consequences if an earthquake occurs without a tsunami.
Earthquakes are best known for the devastation they can cause. Destructions of buildings and structures are caused by soil vibrations or giant tidal waves (tsunamis) that occur during seismic displacements on the seabed. A powerful earthquake begins with the rupture and movement of rocks somewhere deep within the Earth. This location is called the earthquake focus or hypocenter. Its depth is usually no more than 100 km, but sometimes it reaches 700 km. Sometimes the source of an earthquake can be near the surface of the Earth. In such cases, if the earthquake is strong, bridges, roads, houses and other structures are torn and destroyed.
The largest natural disaster is considered to be an earthquake of magnitude 8.2 on July 28, 1976 in the Chinese city of Tangshan, Hebei Province. According to official data from the PRC authorities, the death toll was 242,419 people, however, according to some estimates, the death toll reaches 800 thousand people. At 3:42 local time the city was destroyed by a strong earthquake. There was also destruction in Tianjin and Beijing, just 140 km to the west. As a result of the earthquake, about 5.3 million houses were destroyed or damaged so much that they were uninhabitable. Several aftershocks, the strongest of which had a magnitude of 7.1, led to even greater casualties. The Tangshan earthquake is the second-largest in history after the most destructive earthquake in Shaanxi in 1556. About 830 thousand people died then.
Under an emergency situation (ES) It is generally accepted to understand the situation in a certain territory resulting from an accident, natural or other disaster that may result or have resulted in human casualties, damage to human health or the environment, significant material losses and disruption of the living conditions of the population. Emergencies do not arise immediately; as a rule, they develop gradually from incidents of a man-made, social or natural nature.
Natural disasters are usually unexpected. In a short time they destroy territories, homes, communications, and lead to hunger and disease. In recent years, emergencies of natural origin have tended to increase. In all cases of earthquakes, floods, and landslides, their destructive power increases.
Natural emergencies are divided into
- Geophysical (endogenous) hazardous phenomena: volcanic and geyser eruptions, earthquakes, releases of underground gases to the surface of the earth;
- Geological (exogenous) hazardous phenomena: landslides, screes, landslides, avalanches, mudflows, slope washout, subsidence of loess rocks, soil erosion, abrasion, subsidence (failure) of the earth's surface as a result of karst, dust storms;
- Meteorological hazards: hurricanes (12 – 15 points), storms, storms (9 – 11 points), tornadoes (tornadoes), squalls, vertical whirlwinds, large hail, heavy rain (shower), heavy snowfall, heavy ice, severe frost, severe blizzard, severe heat, heavy fog, drought, dry winds, frost;
- Hydrological hazards: high water levels (floods), high water, rain floods, congestion and jams, wind surges, low water levels, early freeze-up and the appearance of ice on navigable reservoirs and rivers;
- Marine hydrological hazards: tropical cyclones (typhoons), tsunamis, strong waves (5 points or more), strong sea level fluctuations, strong drafts in ports, early ice cover and fast ice, pressure and intense ice drift, impassable (difficult to pass) 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 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 animal diseases: isolated cases of exotic and especially dangerous infectious diseases, epizootics, panzootics, enzootics, infectious diseases of farm animals of unknown etiology;
- Infectious plant diseases: progressive epiphytoty, panphytoty, diseases of agricultural plants of unknown etiology, mass spread of plant pests.
Patterns of natural phenomena
- Each type of emergency is facilitated by a certain spatial location;
- The more intense a dangerous natural phenomenon is, the less often it happens;
- Each natural origin has predecessors - specific characteristics;
- The occurrence of a natural emergency, despite its unexpectedness, can be predicted;
- It is often possible to provide both passive and active measures to protect against natural hazards.
The role of anthropogenic influence on the manifestation of natural emergencies is great. Human activity disturbs the balance in the natural environment. Now, when the scale of use of natural resources has sharply increased, the features of a global environmental crisis have become very noticeable. An important preventive factor that allows reducing the number of natural emergencies is maintaining natural balance.
All natural disasters are interconnected, these are earthquakes and tsunamis, tropical cyclones and floods, volcanic eruptions and fires, poisoning of pastures, death of livestock. When taking protective measures against natural disasters, it is necessary to reduce secondary consequences as much as possible, and with the help of appropriate preparation, eliminate them completely if possible. Studying the causes and mechanisms of natural emergencies is a prerequisite for successful protection against them and the possibility of predicting them. Accurate and timely forecast is an important condition for effective protection against hazardous phenomena. Protection from natural phenomena can be active (construction of engineering structures, reconstruction of natural objects, etc.) and passive (use of shelters),
Geological hazards
- earthquakes
- landslides,
- sat down
- snow avalanches,
- collapses,
- sedimentation of the earth's surface as a result of karst phenomena.
Earthquakes- These are underground impacts and vibrations of the earth's surface, arising as a result of tectonic processes, transmitted over long distances in the form of elastic vibrations. Earthquakes can cause volcanic activity, the fall of small celestial bodies, landslides, dam breaks and other reasons.
The causes of the earthquakes are not fully understood. Stresses arising under the influence of deep tectonic forces deform layers of the earth's rocks. They shrink into folds, and when the overload reaches critical levels, they tear and mix. A fracture in the earth's crust is formed, which is accompanied by a series of shocks and the number of shocks, and the intervals between them are very different. Shocks include foreshocks, mainshocks and aftershocks. The main shock has the greatest strength. People perceive it as very long, although it usually lasts a few seconds.
As a result of research, psychiatrists and psychologists have obtained evidence that aftershocks often have a much more severe mental impact on people than the main shock. There is a feeling of the inevitability of trouble, the person is inactive, while he should be defending himself.
The source of the earthquake– is called a certain volume in the thickness of the Earth, within which energy is released.
The center of the hearth is a conventional point - the hypocenter or focus.
Epicenter of the earthquake- This is the projection of the hypocenter onto the Earth's surface. The greatest destruction occurs around the epicenter, in the pleistoseist region.
The energy of earthquakes is assessed by magnitude (lat. value). is a conditional value that characterizes the total amount of energy released at the source of the earthquake. The strength of the earthquake is assessed according to the international seismic scale MSK - 64 (Mercalli scale). It has 12 conventional gradations - points.
Earthquakes are predicted by recording and analyzing their “predecessors” – foreshocks (preliminary weak tremors), deformation of the earth’s surface, changes in the parameters of geophysical fields, and changes in animal behavior. Until now, unfortunately, there are no methods for reliable prediction of earthquakes. The time frame for the onset 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 earthquake protection measures.
In earthquake-prone areas, the design and construction of buildings and structures is carried out taking into account the possibility of earthquakes. Earthquakes of magnitude 7 and higher are considered dangerous for structures, so construction in areas with magnitude 9 seismicity is uneconomical.
Rocky soils are considered the most reliable seismically. 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 to take into account the relevant rules and regulations (SP and N), which come down to strengthening the structure of structures built in seismic zones.
Anti-seismic action groups
- Preventive, precautionary measures are the study of the nature of earthquakes, the identification of their predecessors, the development of methods for predicting earthquakes;
- Activities that are carried out immediately before the start of an earthquake, during it and after its end. The effectiveness of actions in earthquake conditions 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 an earthquake is panic, during which people, out of fear, cannot meaningfully take measures for rescue and mutual assistance. Panic is especially dangerous in places with the greatest concentration of people - in enterprises, educational institutions and public places.
Deaths and injuries occur when debris from destroyed buildings falls, as well as as a result of people being trapped in the rubble and not receiving timely assistance. As a result of earthquakes, fires, explosions, releases of hazardous substances, transport accidents and other dangerous phenomena can occur.
Volcanic activity- this is the result of active processes that constantly occur in the bowels of the Earth. is a set of phenomena that are associated with the movement of magma in the earth's crust and on its surface. Magma (Greek: thick ointment) is a molten mass of silicate composition that forms deep in the Earth. When magma reaches the earth's surface, it erupts as lava.
There are no gases in the lava that escape during an eruption. This is what distinguishes it from magma.
High water– annually recurring seasonal rises in water levels.
Flood– short-term and non-periodic increase in water level in a river or reservoir.
Floods following one after another can cause floods, and the latter 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 blockage of the river bed during ice drift (jam) or blockage of the river bed by an ice plug under a stationary ice cover (jag).
On sea coasts, floods can be caused by earthquakes, volcanic eruptions, and tsunamis. Floods caused by the action of winds driving water from the sea and increasing the water level due to its retention at the mouth of the river are called surge.
Experts believe that people are at risk from floods if the water layer reaches 1 m and its flow speed is more than 1 m/s. If the water rise reaches 3m, this leads to the destruction of houses.
Flooding can occur even when there is no wind. It may be caused by long waves arising 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 the height of water rise, the area of flooding and the amount of damage: low (small), high (medium), outstanding (large), catastrophic. Low floods can recur after 10-15 years, high ones - after 20-25 years, outstanding ones - after 50-100 years, catastrophic ones - after 100-200 years.
They can last from several to 100 days.
The flood in the valley of the Tigris and Euphrates rivers in Mesopotamia, which occurred 5600 years ago, had very serious consequences. In the Bible, the flood was called the Great Flood.
Tsunamis are long-length marine gravity waves that arise as a result of shifts of large sections of the bottom during underwater earthquakes, volcanic eruptions or other tectonic processes. In the area where they occur, waves reach a height of 1-5m, near the coast - up to 10m, and in bays and river valleys - more than 50m. Tsunamis travel inland over a distance of up to 3 km. The coast of the Pacific and Atlantic oceans is the main area where tsunamis occur. They cause great destruction and pose a threat to people.
Breakwaters, embankments, harbors and jetties provide only partial protection from tsunamis. On the open sea, tsunamis are not dangerous for ships.
Protection of the population from tsunamis - warnings from special services about approaching waves, based on advanced 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 leading to casualties.
Forest fires are uncontrolled burning of vegetation that spontaneously spreads throughout the forest area. In dry weather, the forest dries out so much that any careless handling of fire can cause a fire. In most cases, the culprit of a fire is a person. Forest fires are classified according to the nature of the fire, the speed of spread and the size of the area engulfed in fire.
Depending on the nature of the fire and the composition of the forest, fires are divided into ground fires, crown fires and soil fires. At the beginning of their development, all fires have a grassroots character, and when certain conditions arise, they turn into crown or soil fires. Raised fires are divided according to the parameters of the advance of the edge (the burning strip bordering the outer contour of the fire) into weak, medium and strong. Based on the speed of fire spread, ground and crown fires are divided into stable and fugitive.
Methods of fighting forest fires. The main conditions for the effectiveness of fighting forest fires are the assessment and forecast of fire danger in the forest. State forestry authorities monitor the state of protection in the forest fund.
To organize fire extinguishing, it is necessary to determine the type of fire, its characteristics, directions of its spread, natural barriers (particularly dangerous places for the fire to intensify), the forces and means necessary to fight it.
When extinguishing a forest fire, the following main stages are distinguished: stopping, extinguishing the fire and guarding the fire (preventing the possibility of fire from unknown sources of combustion).
There are two main methods of fire fighting based on the nature of the impact on the combustion process: direct and indirect fire extinguishing.
The first method is used for extinguishing medium and low intensity fires 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 barrier strips along the path of its spread.
Epidemic is a widespread spread of an infectious disease among people, significantly exceeding the incidence rate usually recorded in a given territory.
Types of biological emergencies Epizootics. Infectious animal diseases are a group of diseases that have such common features 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.
All infectious diseases of animals are divided into five groups:
- First group – nutritional infections transmitted through soil, food, and water. The organs of the digestive system are mainly affected. Pathogens are transmitted through infected feed, soil, and manure. Such infections include anthrax, foot and mouth disease, glanders, and brucellosis.
- Second group - respiratory infections - damage to the mucous membranes of the respiratory tract and lungs. These include: parainfluenza, exotic pneumonia, sheep and goat pox, carnivorous plague.
- Third group - vector-borne infections, the mechanism of their transmission is carried out using blood-sucking arthropods. These include: encephalomyelitis, tularemia, equine infectious anemia.
- Fourth group - infections whose pathogens are transmitted through the outer skin without the participation of vectors. These include: tetanus, rabies, cowpox.
- Fifth group - infections with unclear paths of infection, i.e. unskilled group.
Epiphytoty. To assess the scale of plant diseases, the following concepts are used: epiphytoty and panphytoty.
Epiphytoty – the spread of infectious diseases over large areas over a certain period of time.
Panphytotia – mass diseases covering several countries or continents.
Plant diseases are classified according to the following criteria:
- place or phase of plant development (diseases of seeds, seedlings, seedlings, adult plants);
- place of manifestation (local, local, general);
- course (acute, chronic);
- affected crop;
- cause of occurrence (infectious, non-infectious).
Space is one of the elements influencing earthly life.
Dangers threatening from space
Asteroids – These are small planets whose diameter ranges from 1 to 1000 km. Currently, about 300 cosmic bodies are known that can cross the Earth's orbit. In total, according to astronomers, there are approximately 300 thousand asteroids and comets in space.
The meeting of our planet with celestial bodies poses a serious threat to the entire biosphere. Calculations show that 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.
It is planned to develop a system of planetary protection against asteroids and comets, which is based on two principles of protection, namely changing the trajectory of dangerous space objects or destroying it into several parts.
Has a huge impact on earthly life solar radiation.
Solar radiation acts as a powerful health-improving and preventive factor, at the same time it poses a fairly serious danger; excessive solar radiation leads to the development of severe erythema with swelling of the skin and deterioration of health. Special literature describes cases of skin cancer in individuals constantly exposed to excessive solar radiation.