Hydrosphere("hydro" - water) - the water shell on the surface of the Earth, covering oceans, seas, rivers, lakes, swamps, groundwater, mountain and cover glaciers (frozen water).
Types of natural disasters in the hydrosphere are shown in Fig. 1.9.
Rice. 1.9. Types of natural disasters in the hydrosphere.
In table 1.11. classification of waves is given.
Table 1.11
Wave classification
|
Tidal |
Wind (storm) |
Baric |
||
|
Characteristic |
Occurs twice a day. Low tide can cause ships to run aground or reef. The tide creates a wave in rivers up to 3 m high, which is called a bore. In Russia, small forest occurs on rivers flowing into the Mezen Bay |
The predominant height is 4 m, sometimes reaching a height of 18-20 m. Invading land, they cause floods and destruction. |
The propagation speed is 50-800 km/h. Height in open ocean 0.1-5 m, when entering shallow water - 20-30 m, sometimes up to 40-50 m. They invade land by 1-3 km. They reach the shore with a period of 5-90 minutes. |
Like a wave, a tsunami leads to severe consequences, especially when coinciding with a high tide. Reaches 10 m in height in shallow water. |
|
Causes |
They are created by the gravitational forces of the Moon and the Sun and the centrifugal force associated with the rotation of the Earth - Moon system around a common center of gravity. |
Caused by strong winds - hurricanes, typhoons. |
They are formed during the eruption of underwater volcanoes and underwater earthquakes, blasting. |
Caused by cyclones when the pressure at its center drops and forms a bulge up to 1 m high |
The most dangerous waves are tsunamis.
Tsunami- gravitational waves of very long length and height, arising on the surface of the seas and oceans (translated from Japanese - a large wave in the bay).
Tsunami waves are similar to wind waves, but they have a different nature - seismic. The wave length - the distance between adjacent crests - is from 5 to 1500 km, which does not allow the second, third and subsequent waves to be seen.
In Russia, tsunamis are possible on the Kuril Islands, Kamchatka, Sakhalin, and on the Pacific coast.
In table 1.12. The damaging factors of a tsunami are given.
Table 1.12
Damaging factors
The number of waves reaches seven, with the second or third wave being the strongest and causing the most severe destruction. Tsunami force is estimated by magnitude M from 0 to 3 (up to 6 points).
Tsunami harbingers: - Earthquake; - Low tide at inopportune times (rapid exposure of the seabed), lasting up to 30 minutes; - Flight of wild and domestic animals from places of possible flooding to higher ground; - Thunderous noise heard before the waves approach; - The appearance of cracks in the ice cover off the coast.
Actions of the population during a tsunami
River Flood- flooding with water of the area within the river valley and settlements located above the annually flooded floodplain, due to a heavy influx of water as a result of snowmelt or rain, or blockage of the riverbed with ice and slush. The causes of floods and their classification are given in table. 1.13.
Table 1.13
Classification and causes of floods
|
Causes of flooding |
Name floods |
|
Spring melting of snow causing a prolonged rise in water levels |
High water |
|
Heavy rain, downpours, or rapid melting of snow during winter thaws | |
|
Pile of ice floes during spring ice drift, causing water to rise | |
|
Accumulation of slush (loose ice material) in the fall during freeze-up, causing water to rise | |
|
The rise of water in sea estuaries, on the windward shores of lakes, reservoirs, caused by the impact of wind on the water surface |
Wind surge |
|
Break of dams, dams due to landslides, collapses, movement of glaciers |
Breakthrough |
|
Rising water in the river caused by a blockage |
Zavalnoe |
|
Accidents at hydraulic structures |
Breakthrough |
The largest areas of floodplain flooding are observed on rivers flowing to the northern seas - Ob, Yenisei, Lena. Surge floods are observed in the Azov and Caspian Seas, at the mouth of the Neva rivers on the Baltic Sea and the Northern Dvina on the White Sea. In table 1.14 shows the damaging factors of floods.
Table 1.14
Damaging factors
|
Primary |
Secondary |
|
Flooding of the territory with a layer of water of varying thickness (up to 2 m); - duration of standing flood waters (up to 90 days for large rivers, small ones - up to 7 days); - rate of increase in flood water level; water movement speed up to 4 m/s; - erosion and washout of soil in flood zones; - contamination and contamination of the area; - sediments; - destruction of crops and food supply. |
In case of jams - ice pressure on coastal structures and their destruction; - soil lifting, demolition of buildings; - loss of strength of structures; - destruction of communications: as a result of erosion and undermining; - landslides, landslides; - transport accidents; - pollution of the territory. |
Actions of the population during a flood.
The most dangerous phenomena in the hydrosphere include giant seismic waves - tsunami. They occur in the event of an underwater or coastal earthquake, or a major landslide. A sudden rise or collapse of significant sections of the bottom leads to the rise or collapse of a many-kilometer column of water over a large area. As a result, the energy of an earthquake or underwater eruption is transferred to water and surface waves arise, which spread across the World Ocean at enormous speeds (up to 1000 km/h). Colossal energy drives them 10-15 thousand km at intervals of about 10 minutes. In the deep part of the water area they are practically invisible, since due to their large length (up to 150 km) they have a height of up to 1.5 m. When approaching the shore and entering shallow water, the wave slows down, its base begins to slow down against the bottom and the wave energy goes to increase the height to 10-30 m. Long narrow bays (fjords) with steep banks are especially dangerous. Entering the narrowing bay, the wave gradually increases its height, rising to 40-50 m or more.
The tsunami in the Indian Ocean on December 26, 2004 is known for its most widespread catastrophic consequences. Shifts of the ocean floor in the subduction zone of the Java Trench off the coast of Indonesia led to the formation of a powerful earthquake with a magnitude of 8.8 and a strength of 9.3. This one of the most powerful earthquakes recorded triggered a tsunami that killed more than 230 thousand people. Its victims were residents of Indonesia (about 130 thousand dead), Sri Lanka (more than 35 thousand dead), India (about 17 thousand dead), Thailand (more than 8 thousand) and other countries. In different areas, the tsunami consisted of 3-7 waves, 7-27 meters high, moving at speeds from 320 to 800 km/h. In some areas, waves moved inland by 4 km. Giant waves were formed after the Burma Plate, which the Australian plate had been pulling down into the upper mantle for centuries, unexpectedly rose, throwing up a multi-meter layer of water.
To prevent the catastrophic consequences of a tsunami, an international tsunami warning service has been created. It works more efficiently in the Pacific Ocean. The danger of a tsunami leads to the need to change approaches to the choice of location and design of buildings. In particular, planning, purpose and building materials first floors, which allow passing or redirecting the shock force of waves without causing significant damage to the entire building, infrastructure and people. To do this, garages and utility rooms are placed on the ground floor, and the filling between the main load-bearing structures(columns) are made from less durable materials.
Powerful tsunamis are also formed when large masses of rocks, glaciers or underwater landslides collapse into the water. The reason for this may be earthquakes, volcanic eruptions, weathering processes, excess moisture, climate change, etc. Particularly high waves are formed when rocks or glaciers collapse into a deep bay. In these cases, waves are formed hundreds of meters high (the maximum recorded height is 600 m), which rush in a relatively confined space for several hours from coast to coast, gradually calming down. Such events have occurred repeatedly in Alaska, Scandinavia, the Mediterranean and other areas.
There is an assumption about a powerful catastrophe that occurred about 120 thousand years in the Pacific Ocean. Due to the activity of the Mauna Loa volcano in the Hawaiian Islands, a rock with a volume of 120 cubic miles fell into the ocean, and a wave of more than 200 m high rose from the site of the fall. Currently, a similar threat is posed by the dormant volcano Cumbre Vieja in the Canary Islands. If it awakens, a colossal rock may fall into the Atlantic Ocean, causing a wave up to 300 m high. In this case, according to the calculations of American experts, in 9 hours Florida will be covered by a wave 25 meters high.
Not less catastrophic consequences can be caused not by seismic or landslides, but tidal and surge waves in the World Ocean. Typhoons and heavy rainfall contribute to their intensification. The interaction of these two factors can lead to a reversal of river flows, the formation of huge waves and a sharp increase in water levels. The most severe consequences develop in regions with a slight elevation of land above sea level, which include the coastal zones of the Mesopotamian Lowland and the Bay of Bengal (Bangladesh, Burma). Under the influence of heavy rainfall and wind in 1737 and 1876, these territories were flooded with water tens of kilometers from the coast within 2-3 weeks. The water level rose by 10-15 m. In each case, the death toll was hundreds of thousands of people. Events similar in nature, but less catastrophic, occur here every 10-15 years.
Similar, but smaller-scale phenomena also occur in relatively isolated reservoirs. For example, in the Sea of Azov. Here, especially intense floods are formed in the event of a change in the strong southern wind, driving water from the Kerch Strait to the western one. In this case, a large mass of water under wind pressure moves along the shallow bed of the sea, retreating from the western shore (Ukraine) by hundreds of meters and even kilometers and flooding the eastern one (the Azov flood plains of the Krasnodar Territory). In this case, sea level may rise by 2-3 m. Due to the absence of land areas with an elevation above sea level of more than 1.5 m, the abundance of swamps and estuaries, the coastal area is completely covered with water at a distance of up to 20-25 km from the sea. In the fifties, all fishing brigades and canneries in the area were thus destroyed. Azov coast Krasnodar region and hundreds of people died. When the wind weakens, this entire mass of water, due to a level imbalance, begins to move in the opposite direction, forming surge waves (seiches) several meters high and flooding the western coast of the Sea of Azov.
If a similar situation arises in winter time Active hummocking of ice is developing and squeezing it tens of meters onto the shore, which leads to the destruction of engineering structures and ships (the latter in the winter of 2006 in the Taganrog Bay).
Hazardous phenomena associated with terrestrial water bodies are of a much smaller scale and have catastrophic consequences. However, in total they cause no less damage than tsunamis or earthquakes. An example is the events near Novorossiysk in August 2002. Their root cause, of course, was extremely intense precipitation - on August 8, in sixteen hours, 362 mm of precipitation fell on Novorossiysk and the surrounding area, which is the six-month norm. But, the tragic results were amplified by human actions.
The scale of the disaster in the Shirokaya Balka tract is largely related to the spontaneous development of the floodplain, banks and mouth of the stream, and amateur construction large quantity bridges, dams across it to recreation centers and garden plots. It was this, and not the “mythical” tornado, that intensified the consequences of the disaster. Each of these structures, not designed for high water throughput and clogged with debris, stones, fallen trees, became an obstacle to the raging flow and raised the level in the resulting dam by 3-5, and in some areas up to 6-8 meters. Noted by many witnesses, at some point a sharp increase in the water level in the stream (up to 1 meter per minute) is the result of the successive breakthrough of some of these spontaneous dams.
The second group of disasters in the Novorossiysk area on these same days was also caused by precipitation and intensified by human actions, or rather inaction. They are associated with the destruction of dams of overflowing reservoirs on the Durso (Fig. 2.3.) and Tsemess rivers.
The latter was especially catastrophic, because... The burst water flooded a significant part of the industrial and residential zone of Novorossiysk, which led to the destruction of hundreds of houses and the death of dozens of people. And in this case, a decisive contribution to the scale of the incident was made by the lack of attention to the condition of hydraulic structures, the long-uncleaned river bed draining the entire valley, and the development of the floodplain. Raised 1-2 meters above its surface, roads are a kind of dams and dikes that guide water flows, preventing the spread of water, the rapid decrease in its level and enhance the effect of flooding.
It is obvious that similar disasters on large rivers and reservoirs have even more tragic consequences. Life safety problems associated with increased technogenic transformation of our environment and climate change are becoming increasingly acute. Floods have become more frequent in Europe in recent decades, North America, the events that occurred in the North Caucasus in 2002 (only in the Krasnodar Territory the disaster struck at least four times in a year), due to their extraordinary nature and severe consequences, should become the subject of serious geotechnical analysis, and their conclusions should be taken into account when designing new structures and determining criteria technospheric security.
Rice. 2.3. A dam on the Durso River destroyed by a flood (photo by A.E. Kambarova)
Security questions for lecture 5
1. What is the difference between floods and floods?
2. What is a hydrograph?
3. List the main types of river nutrition.
4. What is M.I. Lvovich’s classification based on?
5. List the phases of the water regime.
6. The role of water in the biosphere.
7. What is a hydrograph?
8. How is the drain modulus measured?
10. In what units is physiological evaporation measured?
11. River flow and urbanization.
12. The influence of reservoirs on river flow.
13. What do the concepts of deduction and transpiration characterize?
14. Explain the reasons for fluctuations in the salinity of the World Ocean.
15. What is the difference between the concepts of salinity and mineralization?
16. What is a tsunami?
17. What parameters are the waves characterized by?
18. What is the cause of surface currents in the World Ocean?
Often natural processes and phenomena turn into spontaneous natural phenomena. In cases where they cause damage to the economy and pose a danger to human life, they are called natural disasters . Natural disasters usually include earthquakes, floods, mudflows, landslides, snow drifts, volcanic eruptions, landslides, droughts, hurricanes, storms, etc.
Natural disasters can occur either independently of each other or in conjunction: one of them can lead to another. Some of them often arise as a result of human activity (for example, forest and peat fires, industrial explosions in mountainous areas, during the construction of dams, foundation (development) of quarries, which often leads to landslides, snow avalanches, glacier collapses, etc.) .
Regardless of the source of occurrence, natural disasters are characterized by significant scales and varying durations - from several seconds and minutes (earthquakes, avalanches, limnological disasters) to several hours (mudflows), days (landslides) and months (floods).
Examples of natural disasters
| № | Name | Shell | Features of occurrence and causes | Areas of most frequent distribution in Russia | Consequences |
| 1. | Earthquake | Lithosphere | Shocks and vibrations of the earth's surface caused by ruptures and displacements in the earth's crust | Kamchatka, Kuril Islands, Transbaikalia, Stanovoy Range, Caucasus | Destruction, loss of life, cracks, landslides |
| 2. | Mudflow (mud-stone flow) | Lithosphere | Rain, rapid snowmelt | Caucasus, Urals, Altai, Sayan Mountains, Verkhoyansk Range, Chersky Range | Destruction, destruction of crops, dams |
| 3. | Landslide, collapse | Lithosphere | The influence of gravity; most often appear on slopes composed of alternating water-resistant and aquiferous rocks | On the slopes of river banks, in the mountains, on the shores of the seas, for example, in the Ulyanovsk region on the banks of the Volga, on the banks of the Moscow River, on the Black Sea coast in the Novorossiysk region, etc. | Damage to agricultural land, enterprises, populated areas |
| 4. | Volcanic eruption | Lithosphere | Under the strong pressure of the released gases, magma, melting the surrounding rocks, breaks out to the surface of the earth | Kamchatka, Kuril Islands | Destruction, loss of life |
| 5. | Drought | Atmosphere | Lack of rain, strong winds, drying soils | South of the East European Plain, Urals, Siberia, Ciscaucasia | Death of plants, occurrence of fires |
| 6. | Tornado | Atmosphere | Local heterogeneity of the atmosphere, alternation of warm and cold layers of air. Earth's magnetic field. | European part of Russia – center and south, less often north | Destroys buildings, lifts objects into the air, uproots trees |
| 7. | Hurricane, typhoon (atmospheric vortex with low atmospheric pressure in the center) | Atmosphere | Occurs primarily in the intertropical convergence zone over superheated oceanic areas | Far East | Catastrophic devastation on land and rough seas |
| 8. | Flood | Hydrosphere | Precipitation during rains, melting snow and ice, typhoons, emptying of reservoirs | St. Petersburg, basin of the Amur, Yenisei, Lena rivers | Material damage, personal injury and loss of life |
| 9. | Tsunami | Hydrosphere | Shocks and vibrations of the ocean earth's crust, underwater landslides | Far Eastern coast, Kamchatka, Kuril Islands, Sakhalin | Property damage and loss of life |
During 2009 in the territory Russian Federation More than 900 hazardous natural phenomena were observed, of which 385 caused significant damage to sectors of the economy and the life of the population (in 2008 there were 348). In the cold period there were 85 of them, in the warm period – 300.
The most frequently reported hazardous events were: very heavy rain (heavy downpour) – about 16% and very strong wind (including squalls) – more than 14% of the total. A significant part was also accounted for by hydrological phenomena (mudflows, exceeding dangerous levels of water levels in rivers during periods of spring floods and rain floods, etc.) - more than 14% of the total number of dangerous phenomena.
In a number of cases, individual hazardous events caused significant damage to the economy and livelihoods of the country's population.
Heavy accumulation of wet snow was observed in the Volgograd region on January 23-24, 2009 and in the Tver region on January 28-29, 2009. In five districts of the Volgograd region, 105 power line supports were damaged and toppled; power lines are damaged; in the Tver region, due to an emergency shutdown of 475 transformer substations, there was a disruption in the power supply in 8 districts of the region (322 settlements were left without electricity).
As a result of snow avalanches in January-March 2009 in the regions of the North Caucasus, the Trans-Caucasus Highway, local and federal roads were repeatedly blocked, and several people died.
Very strong winds (gusts up to 25 m/s) in the Lipetsk and Tambov regions on April 18, 2009 led to numerous damage to power lines, and power was cut off in a number of settlements. In the Lipetsk region, due to the loss of power to the water intake, 120 thousand people were left without water for 7 hours, the work of vehicles was hampered, and the roofs of houses were damaged; In the Tambov region, 1,845 houses remained without power supply.
Frosts were observed (temperature -10...-3 o C, in some places down to -12 o C) in Yuzhny federal district during the periods from 10 to 15 and from 20 to 27 April. In the Kabardino-Balkarian Republic, the Republic of North Ossetia - Alania, Krasnodar and Stavropol Territory, Astrakhan and Rostov regions, damage and death of winter, spring, vegetable and seed crops, as well as fruit and berry plantings, were noted.
Severe and prolonged (from late May to August) drought (atmospheric and soil) in the republics of Bashkortostan, Kalmykia, Tatarstan, the Kabardino-Balkarian Republic, the Udmurt Republic, the Astrakhan, Volgograd, Rostov, Samara, and Ulyanovsk regions caused significant damage to grain crops . Crops were written off in the following areas: in the Republic of Tatarstan - 313 thousand hectares, Samara and Orenburg regions– over 1 million 120 thousand hectares, Saratov region – over 555 thousand hectares, Ulyanovsk region – over 116 thousand hectares.
In the Moscow region on June 3, in the Krasnodar and Stavropol territories on July 4, 5, 12 and 13, large hail damaged the roofs of houses, power lines, and agricultural crops.
As a result of very heavy rain in the Republic of Dagestan on September 20-21 and 26-28, 2009, residential buildings were flooded and in some places partially destroyed and flooded personal plots, roads were washed out, and in the Kizilyurt district - 150 m of railway track, which caused a freight train accident.
The presentation “Natural natural phenomena of the hydrosphere” is intended to summarize the “Hydrosphere” section in 6th grade geography lessons. The purpose of this presentation is to summarize the material studied. And also show that water has a powerful destructive force. The presentation shows such natural phenomena of the hydrosphere as mudflows, avalanches, tsunamis, floods and sinkholes. Students can assess the damage caused by these natural disasters. This presentation can be demonstrated both in lessons and during discussions within the framework of the decade of geography.
View document contents
“Presentation on geography on the topic “Natural natural phenomena of the hydrosphere” (grade 6)”
Spontaneous natural
hydrosphere phenomena
Zaitseva Elena Vladimirovna
geography teacher
MBOU Irkutsk Secondary School No. 73
FLOOD -
This is a significant flooding of an area as a result of rising water levels in a river, lake or sea during snowmelt, rainfall, wind surges, congestion, etc.
Tsunami in Thailand,
Tsunami in Japan,
Heavy rainfall led to a mudflow
in Crimea.
Due to heavy rainfall, the village of St. Lorenz in Austria
was completely swept away by the mudflow.
Due to a sharp rise in water levels due to heavy rains
The village of Arshan was flooded and mudflows occurred.
SNOW AVALANCHE is a mass of snow falling or moving at a speed of 20 - 30 m/s or more.
Northern Norway
Everest
An avalanche occurred on the India-Pakistan border
Sinkhole –
This is a sinkhole of natural origin.
A sinkhole occurs when groundwater erodes soil and rocks, causing the ground to fall into the resulting void.
What is the importance of water for the nature of the Earth?
Water is the basis of life on Earth. Life itself originated in water. Water is sediment. Living organisms contain water. She is the main participant in many chemical reactions. Water is a habitat for many organisms.
What parts does the hydrosphere consist of?
The hydrosphere consists of the waters of the World Ocean, land waters, groundwater and glaciers.
How are all parts of the hydrosphere connected to each other?
All parts of the hydrosphere are interconnected by the water cycle.
Questions and assignments
1. What adverse natural phenomena are associated with the hydrosphere? Which ones are available in your area?
The water element is the cause of destructive natural disasters that pose a great threat to humans. Common adverse events are floods and avalanches.
2. What are the main causes and consequences of river floods?
Of all the natural disasters that occur on Earth, floods cause the greatest damage. This is the flooding of an area with water as a result of its rising in the sea, river or lake. Floods occur on 3/4 of the land area. Water floods settlements, buildings, and fields. Buildings are destroyed, crops are destroyed, and there are casualties. Floods on rivers occur due to prolonged rains, rapid melting of snow, and dam breaks. On the shores of the World Ocean they happen when the wind pushes water onto land. To protect against them, special structures are erected - dams.
3. What is the importance of rivers and lakes in the life and economic activities of people?
River waters are used for irrigation in arid areas and for the construction of hydroelectric power stations. Large rivers are used for navigation. Lakes most often have recreational value. Many lakes become objects of fisheries. The waters of some lakes are used in industry and energy for cooling.
4. How has human water consumption changed over time?
Human water consumption is growing every year. During the 20th century, water consumption increased more than 12 times.
5. Why are dams built on rivers and reservoirs created?
Dams and reservoirs are built on rivers to generate energy from hydroelectric power plants.
6. What influence does man have on the hydrosphere?
Half of all water used by people is spent on irrigating fields. Another 1/4 of the share is consumed by industry. In third place are urban services and human needs. This use causes pollution of the hydrosphere. The waters are becoming polluted chemicals, mechanical particles. Thermal pollution also occurs, which affects the microclimate. Many rivers and lakes have become shallow due to excessive water intake. Groundwater pollution and depletion occurs.
7. Why should a person care about the quantity and quality of water?
Fresh water reserves are small. They are distributed unevenly across the territory of our planet. Human water consumption is growing every year. Many territories already today experience a severe shortage of drinking water. In addition, the degree of pollution of the hydrosphere is growing. Life without water is impossible for humans, so it is necessary to take care of the state of the hydrosphere.
8. If chemicals are used in the river basin and in the fields, is it possible for them to appear at the river mouth and why?
The chemicals will almost certainly end up at the river mouth. Together with precipitation, chemicals will flow into the river waters. The water in the river moves towards the mouth. Therefore, all substances dissolved in the water will end up at the mouth of the river.
