The temperature of the earth's crust. Shells of the Earth
Goals and objectives of the lesson:
- introduce students to the main shells of the Earth;
- consider the features of the internal structure of the Earth, the properties of the earth's crust;
- give an idea of how to study the earth's crust.
Educational and visual complex:
- The globe,
- diagram of the structure of the earth's crust (multimedia presentation),
- textbook for grade 6 “Initial Geography Course” Gerasimova T.P., Neklyukova N.P.
Forms of the lesson:
Acquaintance with the main shells of the Earth, their definition; work with the scheme “Internal structure of the Earth”; work with the table "Earth's crust and features of its structure"; a story about how to study the earth's crust.
Terms and concepts:
- atmosphere,
- hydrosphere,
- lithosphere,
- Earth's crust,
- mantle,
- core of the earth,
- mainland crust,
- oceanic crust,
- Mohorović section,
- ultra-deep wells.
Geographic features:
Kola Peninsula.
Explanation of the new material:
1. Explanatory reading of the textbook, note-taking.
Underline with a pencil and write in a notebook: (using a multimedia presentation).
Outer shells of the earth:
- Air - gaseous shell - atmosphere
- water - water shell - hydrosphere
- rocks that make up the land and the bottom of the oceans - Earth's crust
- living organisms, together with the environment in which they live, constitute biosphere.
2. The structure of the Earth (we consider Fig. 22, p. 39). Use of multimedia presentation. Commented reading, drawing up an abstract in a notebook.
The lithosphere is a solid shell of the Earth, including the earth's crust and the upper part of the mantle. The thickness of the lithosphere is on average from 70 to 250 km.
Radius of the Earth (equatorial) = 6378 km
3. Properties of the earth's crust. Inclusion in the abstract of work with fig. 23 p.40 (using multimedia presentation).
The Earth's crust is a hard stone shell of the Earth, consisting of solid minerals and rocks.
Earth's crust
4. Solving problems for determining the temperature that changes with immersion into the depths of the Earth.
From the mantle, the internal heat of the Earth is transferred to the earth's crust. The upper layer of the earth's crust - up to a depth of 20-30m is affected by external temperatures, and below the temperature gradually rises: for every 100m of depth by + 3C. Deeper, the temperature is already largely dependent on the composition of the rocks.
Task: What is the temperature of rocks in a mine where coal is mined, if its depth is 1000m, and the temperature of the earth's crust layer, which no longer depends on the season, is + 10C
Decide by action:
- By how many degrees does the temperature of the earth's crust rise in the mine:
- What will be the temperature of the earth's crust in the mine?
10С+(+30С)= +40С
Temperature = +10С +(1000:100 3С)=10С +30С =40С
Solve the problem: What is the temperature of the earth's crust in the mine, if its depth is 1600m, and the temperature of the earth's crust layer, which does not depend on the season, is -5 C?
Air temperature \u003d (-5С) + (1600: 100 3С) \u003d (-5С) + 48С \u003d + 43С.
Write down the condition of the problem and solve it at home:
What is the temperature of the earth's crust in the mine, if its depth is 800 m, and the temperature of the earth's crust layer, which does not depend on the season, is +8°C?
Solve the problems given in the lesson summary
5. Study of the earth's crust. Working with fig. 24 p.40, the text of the textbook.
Drilling of the Kola super-deep well began in 1970, its depth is up to 12-15 km. Calculate what part of the earth's radius this is.
R Earth = 6378 km (equatorial)
6356 km (polar) or meridional
530-531 part of the equatorial.
The depth of the deepest mine in the world is 4 times less. Despite numerous studies, we still know very little about the bowels of our own planet. In a word, if we turn again to the above comparison, we still cannot “pierce the shell” in any way.
- Consolidation of new material. Using a multimedia presentation .
Tests and tasks for verification.
1. Determine the shell of the Earth: Earth's crust.
A. aerial
B. hard.
G. water.
Check key:
2. Determine which shell of the Earth we are talking about: Earth's crust
a/ closest to the center of the earth
b/ thickness from 5 to 70cm
c/ translated from Latin “veil”
g / temperature of the substance +4000 C + 5000 C
e/ upper shell of the Earth
e/ thickness about 2900 km
g/ special state of matter: solid and plastic
h/ consists of continental and oceanic parts
and / the main element of the composition is iron.
Check key:
3. According to its internal structure, the earth is sometimes compared to a chicken egg. What do they want to show this comparison?
Homework: §16, assignments and questions after the paragraph, task in the notebook.
The material used by the teacher when explaining a new topic.
Earth's crust.
The Earth's crust on the scale of the entire Earth represents the thinnest film and is negligible compared to the radius of the Earth. It reaches a maximum thickness of 75 km under the mountain ranges of the Pamirs, Tibet, the Himalayas. despite its small thickness, the earth's crust has a complex structure.
Its upper horizons are quite well studied by drilling wells.
The structure and composition of the earth's crust under the oceans and on the continents are very different. Therefore, it is customary to distinguish two main types of the earth's crust - oceanic and continental.
The earth's crust of the oceans occupies approximately 56% of the planet's surface, and its main feature is a small thickness - an average of about 5-7 km. But even such a thin earth's crust is divided into two layers.
The first layer is sedimentary, represented by clays, lime silts. The second layer is composed of basalts - products of volcanic eruptions. The thickness of the basalt layer at the bottom of the oceans does not exceed 2 km.
The continental (continental) crust occupies an area smaller than the oceanic one, about 44% of the planet's surface. The continental crust is thicker than the oceanic, its average thickness is 35-40 km, and in the mountains it reaches 70-75 km. It consists of three layers.
The upper layer is composed of a variety of sediments, their thickness in some depressions, for example, in the Caspian lowland, is 20-22 km. Shallow water deposits predominate – limestones, clays, sands, salts and gypsum. The age of the rocks is 1.7 billion years.
The second layer - granite - it is well studied by geologists, because. there are exits to the surface, and attempts were made to drill it, although attempts to drill the entire layer of granite were unsuccessful.
The composition of the third layer is not very clear. It is assumed that it must be composed of rocks such as basalts. Its thickness is 20-25 km. At the base of the third layer, the Mohorovichic surface is traced.
Moho surface.
In 1909 on the Balkan Peninsula, near the city of Zagreb, there was a strong earthquake. Croatian geophysicist Andrija Mohorovichic, studying the seismogram recorded at the time of this event, noticed that at a depth of about 30 km, the wave speed increases significantly. This observation was confirmed by other seismologists. This means that there is a certain section that limits the earth's crust from below. To designate it, a special term was introduced - the Mohorovichic surface (or the Moho section).
Under the crust at depths from 30-50 to 2900 km is the Earth's mantle. What does it consist of? Mainly from rocks rich in magnesium and iron.
The mantle occupies up to 82% of the planet's volume and is divided into upper and lower. The first lies below the Moho surface to a depth of 670 km. The rapid drop in pressure in the upper part of the mantle and the high temperature lead to the melting of its substance.
At a depth of 400 km under the continents and 10-150 km under the oceans, i.e. in the upper mantle, a layer was discovered where seismic waves propagate relatively slowly. This layer was called the asthenosphere (from the Greek "asthenes" - weak). Here, the proportion of the melt is 1-3%, more plastic. Than the rest of the mantle, the asthenosphere serves as a “lubricant” along which rigid lithospheric plates move.
Compared to the rocks that make up the earth's crust, the rocks of the mantle are distinguished by a high density and the speed of propagation of seismic waves in them is noticeably higher.
In the very "basement" of the lower mantle - at a depth of 1000 km and up to the surface of the core - the density gradually increases. What the lower mantle consists of remains a mystery.
It is assumed that the surface of the nucleus consists of a substance with the properties of a liquid. The boundary of the core is at a depth of 2900 km.
But the inner region, starting from a depth of 5100 km, behaves like a solid body. This is due to very high pressure. Even at the upper boundary of the core, the theoretically calculated pressure is about 1.3 million atm. and in the center it reaches 3 million atm. The temperature here can exceed 10,000C. Each cube. cm of the substance of the earth's core weighs 12 -14 g.
Obviously, the substance of the outer core of the Earth is smooth, almost like a cannonball. But it turned out that the “border” drops reach 260 km.
- the earth's crust is oceanic.
- continental crust
- mantle
- core
a. consists of granite, basalt and sedimentary rocks.
b. temperature +2000, viscous state, closer to solid.
in. layer thickness 3-7 km.
g. temperature from 2000 to 5000C, solid, consists of two layers.
_______________________________________________________________________________
- Solve problems:
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The Earth is located close enough to the Sun that the energy received is enough to maintain heat and the existence of water in liquid form. This is the main reason why our planet is habitable.
As we remember from geography lessons, the Earth consists of different layers. The further to the center of the planet, the more heated the situation. Fortunately for us, on the crust, the uppermost geological layer, the temperature is relatively stable and comfortable. However, its meanings can vary greatly depending on the place and time.
Johan Swanepoel | shutterstock.com
Earth structure
Like other terrestrial planets, our planet is composed of silicate rocks and metals that differentiate between a solid metal core, a molten outer core, a silicate mantle, and a crust. The inner core has an approximate radius of 1220 km, and the outer one about 3400 km.
Then the mantle and the earth's crust follow. The thickness of the mantle is 2890 km. This is the thickest layer of the Earth. It consists of silicate rocks rich in iron and magnesium. The high temperatures inside the mantle make the solid silicate material sufficiently ductile.
The upper layer of the mantle is divided into the lithosphere and the asthenosphere. The first consists of a crust and a cold, rigid upper mantle, while the asthenosphere has some plasticity, which makes the lithosphere covering it unstable and mobile.
Earth's crust
The crust is the outer shell of the Earth and makes up only 1% of its total mass. The thickness of the bark varies depending on the location. On the continents, it can reach 30 km, and under the oceans - only 5 km.
The shell consists of many igneous, metamorphic and sedimentary rocks and is represented by a system of tectonic plates. These plates float above the Earth's mantle, and presumably convection in the mantle causes them to be in constant motion.
Sometimes tectonic plates collide, pull apart, or slide against each other. All three types of tectonic activity underlie the formation of the earth's crust and lead to periodic renewal of its surface over millions of years.
Temperature range
On the outer layer of the crust, where it comes into contact with the atmosphere, its temperature coincides with that of the air. Thus, it can heat up to 35 ° C in the desert and be below zero in Antarctica. The average surface temperature of the bark is about 14 °C.
As you can see, the range of values is quite wide. But it is worth considering the fact that most of the earth's crust lies under the oceans. Away from the sun, where it meets water, the temperature can be only 0...+3 °C.
If you start digging a hole in the continental crust, the temperature will rise noticeably. For example, at the bottom of the world's deepest mine "Tau Tona" (3.9 km) in South Africa, it reaches 55 ° C. The miners who work there all day cannot do without air conditioning.
Thus, average surface temperatures can vary from sweltering hot to bitterly cold depending on location (on land or underwater), seasons, and time of day.
Yet the Earth's crust remains the only place in the solar system where temperatures are stable enough for life to continue to thrive. Add to this our viable atmosphere and protective magnetosphere, and you will realize that we are really very lucky!
The earth's crust is of great importance for our life, for the exploration of our planet.
This concept is closely related to others that characterize the processes occurring inside and on the surface of the Earth.
What is the earth's crust and where is it located
The earth has an integral and continuous shell, which includes: the earth's crust, troposphere and stratosphere, which are the lower part of the atmosphere, hydrosphere, biosphere and anthroposphere.
They closely interact, penetrating each other and constantly exchanging energy and matter. It is customary to call the earth's crust the outer part of the lithosphere - the solid shell of the planet. Most of its outer side is covered by the hydrosphere. The rest, a smaller part, is affected by the atmosphere.
Under the Earth's crust is a denser and more refractory mantle. They are separated by a conditional border, named after the Croatian scientist Mohorovich. Its feature is a sharp increase in the speed of seismic vibrations.
Various scientific methods are used to gain insight into the earth's crust. However, obtaining specific information is possible only by means of drilling to a greater depth.
One of the objectives of such a study was to establish the nature of the boundary between the upper and lower continental crust. The possibilities of penetration into the upper mantle with the help of self-heating capsules made of refractory metals were discussed.
The structure of the earth's crust
Under the continents, its sedimentary, granite and basalt layers are distinguished, the thickness of which in the aggregate is up to 80 km. Rocks, called sedimentary rocks, were formed as a result of the deposition of substances on land and in water. They are predominantly in layers.
- clay
- shales
- sandstones
- carbonate rocks
- rocks of volcanic origin
- coal and other rocks.
The sedimentary layer helps to learn more about the natural conditions on earth that were on the planet in time immemorial. Such a layer may have a different thickness. In some places it may not exist at all, in others, mainly in large depressions, it may be 20-25 km.
The temperature of the earth's crust
An important energy source for the inhabitants of the Earth is the heat of its crust. The temperature increases as you go deeper into it. The 30-meter layer closest to the surface, called the heliometric layer, is associated with the heat of the sun and fluctuates depending on the season.
In the next, thinner layer, which increases in continental climates, the temperature is constant and corresponds to the indicators of a particular measurement site. In the geothermal layer of the crust, the temperature is related to the internal heat of the planet and increases as you go deeper into it. It is different in different places and depends on the composition of the elements, the depth and conditions of their location.
It is believed that the temperature rises on average by three degrees as it deepens for every 100 meters. Unlike the continental part, the temperature under the oceans is rising faster. After the lithosphere, there is a plastic high-temperature shell, the temperature of which is 1200 degrees. It is called the asthenosphere. It has places with molten magma.
Penetrating into the earth's crust, the asthenosphere can pour out molten magma, causing volcanic phenomena.
Characteristics of the Earth's crust
The Earth's crust has a mass of less than half a percent of the total mass of the planet. It is the outer shell of the stone layer in which the movement of matter occurs. This layer, which has a density half that of the Earth. Its thickness varies within 50-200 km.
The uniqueness of the earth's crust is that it can be of continental and oceanic types. The continental crust has three layers, the upper of which is formed by sedimentary rocks. The oceanic crust is relatively young and its thickness varies little. It is formed due to the substances of the mantle from oceanic ridges.
earth's crust characteristic photo
The thickness of the crust under the oceans is 5-10 km. Its feature is in constant horizontal and oscillatory movements. Most of the crust is basalt.
The outer part of the earth's crust is the hard shell of the planet. Its structure is distinguished by the presence of mobile areas and relatively stable platforms. Lithospheric plates move relative to each other. The movement of these plates can cause earthquakes and other cataclysms. The regularities of such movements are studied by tectonic science.
Functions of the earth's crust
The main functions of the earth's crust are:
- resource;
- geophysical;
- geochemical.
The first of them indicates the presence of the resource potential of the Earth. It is primarily a set of mineral reserves located in the lithosphere. In addition, the resource function includes a number of environmental factors that ensure the life of humans and other biological objects. One of them is the tendency to form a hard surface deficit.
you can't do that. save our earth photo
Thermal, noise and radiation effects realize the geophysical function. For example, there is a problem of natural radiation background, which is generally safe on the earth's surface. However, in countries such as Brazil and India, it can be hundreds of times higher than the allowable one. It is believed that its source is radon and its decay products, as well as some types of human activity.
The geochemical function is associated with problems of chemical pollution harmful to humans and other representatives of the animal world. Various substances with toxic, carcinogenic and mutagenic properties enter the lithosphere.
They are safe when they are in the bowels of the planet. Zinc, lead, mercury, cadmium and other heavy metals extracted from them can be very dangerous. In processed solid, liquid and gaseous form, they enter the environment.
What is the Earth's crust made of?
Compared to the mantle and core, the Earth's crust is fragile, tough, and thin. It consists of a relatively light substance, which includes about 90 natural elements in its composition. They are found in different places of the lithosphere and with varying degrees of concentration.
The main ones are: oxygen silicon aluminum, iron, potassium, calcium, sodium magnesium. 98 percent of the earth's crust is made up of them. Including about half is oxygen, more than a quarter - silicon. Due to their combinations, minerals such as diamond, gypsum, quartz, etc. are formed. Several minerals can form a rock.
- An ultra-deep well on the Kola Peninsula made it possible to get acquainted with mineral samples from a depth of 12 km, where rocks similar to granites and shale were found.
- The greatest thickness of the crust (about 70 km) was revealed under the mountain systems. Under the flat areas it is 30-40 km, and under the oceans - only 5-10 km.
- A significant part of the crust forms an ancient low-density upper layer, consisting mainly of granites and shales.
- The structure of the earth's crust resembles the crust of many planets, including those on the Moon and their satellites.
Open lesson in geography in grade 6
on the topic: "The internal structure of the Earth."
Teacher: Proskurina N.P.
Target: to acquaint students with the main (inner) shells of the Earth, their structure and composition; give an idea of how to study the earth's crust; develop memory, speech, logical thinking; develop respect for nature.
Equipment:
atlases, physical map of the world, table "Internal structure of the Earth", boat.
During the classes.
Organizational start.
Are you ready for the lesson?
Then let's start the lesson.
In the 6th grade, we have already studied the topic "Plan and Map", but then we will study the shells of the Earth in the following sequence: "Lithosphere", "Hydrosphere", "Atmosphere", "Biosphere". Let's remember:
What part of the Earth is called the lithosphere?
What is the hydrosphere?
Atmosphere?
Biosphere?
We have come to the topic “Lithosphere”, but we will not begin to study it until we check how you remember what you have already studied earlier.
Questions:
1. What is the scale? What kinds of it do you know?
2. Determine the relative and absolute height of the hill.
3. Define the name of the object with coordinates 28 y. sh. and 138 c. (Lake Eyre - North.)
4. Calculate the distance from the geographic north pole to the equator. (90 times 111 km equals 9990).
5. Which city is located higher?
a) Delhi or Beijing.
b) Mexico City or Brasilia.
Exploring a new topic.
a) the message of the topic, the purpose of the lesson;
b) learning a new topic:
We have the most modern ship, but not for underwater travel, but for underground travel.
Gradually delving into the bowels of the Earth, we will get acquainted with its internal structure. You will enter your observational data in a table.
Earth's crust on the scale of the entire Earth is the thinnest film. It consists of solid minerals and rocks, i.e. its state is solid; The temperature rises by 3 degrees every 100 m. Despite the small power, the earth's crust has a complex structure.
Mantle.
Core.
Fizkultminutka.
Methods for studying the earth's depths.
c) primary generalization:
1. What is the internal structure of the Earth?
2. According to its internal structure, the earth is sometimes compared to a chicken egg. What do they want to show this comparison?
3. Build a pie chart "The internal structure of the Earth", showing the proportion of the volume of the core - 17%, the mantle - 82%, the earth's crust - 1%, in the total volume of the planet.
4. Tell us how the temperature (PRESSURE) changes in the bowels of the Earth.
Fill in the table "Types of the earth's crust" using Figure 23.
"Find matches."
2. Earth's crust of the continental type. b) The temperature is 2000 degrees, the state is viscous, (solid).
3. Mantle. c) The thickness of the layer is 3–7 km.
4. Core. d) Temperature 2000 - 5000 degrees, solid, from two layers.
Why study the earth's crust?
In what ways can this be done?
The task of knowing the facts.
Homework: No. 16; question 5.
Kirill Degtyarev, Research Fellow, Lomonosov Moscow State University M. V. Lomonosov.
In our country, rich in hydrocarbons, geothermal energy is a kind of exotic resource that, in the current state of affairs, is unlikely to compete with oil and gas. Nevertheless, this alternative form of energy can be used almost everywhere and quite efficiently.
Photo by Igor Konstantinov.
Change in soil temperature with depth.
Temperature increase of thermal waters and dry rocks containing them with depth.
Change in temperature with depth in different regions.
The eruption of the Icelandic volcano Eyjafjallajökull is an illustration of violent volcanic processes occurring in active tectonic and volcanic zones with a powerful heat flow from the earth's interior.
Installed capacities of geothermal power plants by countries of the world, MW.
Distribution of geothermal resources on the territory of Russia. The reserves of geothermal energy, according to experts, are several times higher than the energy reserves of organic fossil fuels. According to the Geothermal Energy Society Association.
Geothermal energy is the heat of the earth's interior. It is produced in the depths and comes to the surface of the Earth in different forms and with different intensity.
The temperature of the upper layers of the soil depends mainly on external (exogenous) factors - sunlight and air temperature. In summer and during the day, the soil warms up to certain depths, and in winter and at night it cools down following the change in air temperature and with some delay, increasing with depth. The influence of daily fluctuations in air temperature ends at depths from a few to several tens of centimeters. Seasonal fluctuations capture deeper layers of soil - up to tens of meters.
At a certain depth - from tens to hundreds of meters - the temperature of the soil is kept constant, equal to the average annual air temperature near the Earth's surface. This is easy to verify by going down into a fairly deep cave.
When the average annual air temperature in a given area is below zero, this manifests itself as permafrost (more precisely, permafrost). In Eastern Siberia, the thickness, that is, the thickness, of year-round frozen soils reaches 200-300 m in places.
From a certain depth (its own for each point on the map), the action of the Sun and the atmosphere weakens so much that endogenous (internal) factors come first and the earth's interior is heated from the inside, so that the temperature begins to rise with depth.
The heating of the deep layers of the Earth is associated mainly with the decay of the radioactive elements located there, although other sources of heat are also named, for example, physicochemical, tectonic processes in the deep layers of the earth's crust and mantle. But whatever the cause, the temperature of rocks and associated liquid and gaseous substances increases with depth. Miners face this phenomenon - it is always hot in deep mines. At a depth of 1 km, thirty-degree heat is normal, and deeper the temperature is even higher.
The heat flow of the earth's interior, reaching the surface of the Earth, is small - on average, its power is 0.03-0.05 W / m 2,
or about 350 Wh/m 2 per year. Against the background of the heat flow from the Sun and the air heated by it, this is an imperceptible value: the Sun gives each square meter of the earth's surface about 4,000 kWh annually, that is, 10,000 times more (of course, this is on average, with a huge spread between polar and equatorial latitudes and depending on other climatic and weather factors).
The insignificance of the heat flow from the depths to the surface in most of the planet is associated with the low thermal conductivity of rocks and the peculiarities of the geological structure. But there are exceptions - places where the heat flow is high. These are, first of all, zones of tectonic faults, increased seismic activity and volcanism, where the energy of the earth's interior finds a way out. Such zones are characterized by thermal anomalies of the lithosphere, here the heat flow reaching the Earth's surface can be many times and even orders of magnitude more powerful than the "usual" one. A huge amount of heat is brought to the surface in these zones by volcanic eruptions and hot springs of water.
It is these areas that are most favorable for the development of geothermal energy. On the territory of Russia, these are, first of all, Kamchatka, the Kuril Islands and the Caucasus.
At the same time, the development of geothermal energy is possible almost everywhere, since the increase in temperature with depth is a ubiquitous phenomenon, and the task is to “extract” heat from the bowels, just as mineral raw materials are extracted from there.
On average, the temperature increases with depth by 2.5-3 o C for every 100 m. The ratio of the temperature difference between two points lying at different depths to the difference in depth between them is called the geothermal gradient.
The reciprocal is the geothermal step, or the depth interval at which the temperature rises by 1 o C.
The higher the gradient and, accordingly, the lower the step, the closer the heat of the Earth's depths approaches the surface and the more promising this area is for the development of geothermal energy.
In different areas, depending on the geological structure and other regional and local conditions, the rate of temperature increase with depth can vary dramatically. On the scale of the Earth, fluctuations in the values of geothermal gradients and steps reach 25 times. For example, in the state of Oregon (USA) the gradient is 150 o C per 1 km, and in South Africa - 6 o C per 1 km.
The question is, what is the temperature at great depths - 5, 10 km or more? If the trend continues, the temperature at a depth of 10 km should average about 250-300 o C. This is more or less confirmed by direct observations in ultra-deep wells, although the picture is much more complicated than a linear increase in temperature.
For example, in the Kola super-deep well drilled in the Baltic crystalline shield, the temperature to a depth of 3 km changes at a rate of 10 ° C / 1 km, and then the geothermal gradient becomes 2-2.5 times greater. At a depth of 7 km, a temperature of 120 o C was already recorded, at 10 km - 180 o C, and at 12 km - 220 o C.
Another example is a well laid in the Northern Caspian, where at a depth of 500 m a temperature of 42 o C was recorded, at 1.5 km - 70 o C, at 2 km - 80 o C, at 3 km - 108 o C.
It is assumed that the geothermal gradient decreases starting from a depth of 20-30 km: at a depth of 100 km, the estimated temperatures are about 1300-1500 o C, at a depth of 400 km - 1600 o C, in the Earth's core (depths of more than 6000 km) - 4000-5000 o WITH.
At depths up to 10-12 km, the temperature is measured through drilled wells; where they do not exist, it is determined by indirect signs in the same way as at greater depths. Such indirect signs may be the nature of the passage of seismic waves or the temperature of the erupting lava.
However, for the purposes of geothermal energy, data on temperatures at depths of more than 10 km are not yet of practical interest.
There is a lot of heat at depths of several kilometers, but how to raise it? Sometimes nature itself solves this problem for us with the help of a natural coolant - heated thermal waters that come to the surface or lie at a depth accessible to us. In some cases, the water in the depths is heated to the state of steam.
There is no strict definition of the concept of "thermal waters". As a rule, they mean hot underground waters in a liquid state or in the form of steam, including those that come to the surface of the Earth with a temperature above 20 ° C, that is, as a rule, higher than the air temperature.
The heat of groundwater, steam, steam-water mixtures is hydrothermal energy. Accordingly, energy based on its use is called hydrothermal.
The situation is more complicated with the production of heat directly from dry rocks - petrothermal energy, especially since sufficiently high temperatures, as a rule, begin from depths of several kilometers.
On the territory of Russia, the potential of petrothermal energy is a hundred times higher than that of hydrothermal energy - 3,500 and 35 trillion tons of standard fuel, respectively. This is quite natural - the warmth of the Earth's depths is everywhere, and thermal waters are found locally. However, due to obvious technical difficulties, most of the thermal waters are currently used to generate heat and electricity.
Waters with temperatures from 20-30 to 100 o C are suitable for heating, temperatures from 150 o C and above - and for generating electricity at geothermal power plants.
In general, geothermal resources on the territory of Russia, in terms of tons of standard fuel or any other unit of energy measurement, are about 10 times higher than fossil fuel reserves.
Theoretically, only geothermal energy could fully meet the energy needs of the country. In practice, at the moment, in most of its territory, this is not feasible for technical and economic reasons.
In the world, the use of geothermal energy is most often associated with Iceland - a country located at the northern end of the Mid-Atlantic Ridge, in an extremely active tectonic and volcanic zone. Probably everyone remembers the powerful eruption of the Eyjafjallajökull volcano in 2010.
It is thanks to this geological specificity that Iceland has huge reserves of geothermal energy, including hot springs that come to the surface of the Earth and even gushing in the form of geysers.
In Iceland, more than 60% of all energy consumed is currently taken from the Earth. Including due to geothermal sources, 90% of heating and 30% of electricity generation are provided. We add that the rest of the electricity in the country is produced by hydroelectric power plants, that is, also using a renewable energy source, thanks to which Iceland looks like a kind of global environmental standard.
The "taming" of geothermal energy in the 20th century helped Iceland significantly economically. Until the middle of the last century, it was a very poor country, now it ranks first in the world in terms of installed capacity and production of geothermal energy per capita, and is in the top ten in terms of absolute installed capacity of geothermal power plants. However, its population is only 300 thousand people, which simplifies the task of switching to environmentally friendly energy sources: the need for it is generally small.
In addition to Iceland, a high share of geothermal energy in the total balance of electricity production is provided in New Zealand and the island states of Southeast Asia (Philippines and Indonesia), the countries of Central America and East Africa, whose territory is also characterized by high seismic and volcanic activity. For these countries, at their current level of development and needs, geothermal energy makes a significant contribution to socio-economic development.
(Ending follows.)
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