INTERNAL STRUCTURE OF THE EARTH explains
There is disagreement among scientists regarding the internal structure of the Earth. There is no complete consensus yet on the thickness, density, temperature, weight of the layers found underground and the nature of the substances found there. Nevertheless, efforts have been made to obtain information regarding the internal structure of the Earth by collecting evidence based on temperature, pressure, density, meteors and seismic waves. The inner part of the earth is divided into three parts – 1. Crust, 2. Mantle and 3. Central part (Core).
Crust: The upper part of the earth is called earth’s crust. This is an area up to 34 km inland. It is mainly made of basalt rocks. It has two parts – 1. Sial (SiAl) and 2. Seema (SiMa). There is abundance of silicon and aluminum in the sial region and silicon and magnesium in the border region. Average density of karst part – 2.7 g/cm. Is. It occupies 0.5% of the total volume of the Earth.
Composition of the earth’s crust: Oxygen is the most by weight (46.60%), silicon is in the second place (27.72%), aluminum is in the third place (8.13%), iron is in the fourth place (5%), calcium is in the fifth place (3.63%). %), Sodium is at sixth place (2.83%), Potassium is at seventh place (2.59%) and Magnesium is at eighth place (2.09%). That means, approximately 98% of the entire earth’s crust is made up of the above eight elements. The remaining part is made up of titanium, hydrogen, phosphorus, manganese, Sulphur, carbon, nickel and other substances.
Mantle: This 2,900 km thick area is mainly made up of basalt rocks. Magma chambers are found in this part of the mantle. Its average density is 3.5 g/cm. to 5.5 g/cm. Is. It occupies 83% of the total volume of the Earth.
Konrad Discontinuity The boundary zone between the upper crust and the lower crust is called Konrad Discontinuity.
Mohovicic-Discontinuity: The boundary region between the crust and the mantle is called Mohovicic discontinuity.
Repeti Discontinuity The boundary zone between the upper mantle and the lower is called Repeti Discontinuity.
Gutenberg-Wishart Discontinuity The boundary region of the lower mantle and upper core is called the Gutenberg-Wishart Discontinuity.
Lehmann discontinuity The boundary region between the outer core and the inner core is called Lehmann discontinuity.
Central part (Core): The central part (core) of the Earth is made of nickel and iron. Its average density is 13 grams/cm. Is. The central part of the Earth is probably in liquid or plastic state. It occupies 16% of the total volume of the Earth.
The average density of the Earth is 5.5 g/cm. And the average radius is about 6370 km.
As the earth goes down, the temperature increases by 1°C for every 32 meters depth.
The lowest area on Earth’s land surface is the area around the Dead Sea in Jordan. This area is on average 400 meters below sea level.
Pythagoras first told that the Earth is round and it hangs freely in the sky. Sir Isaac Newton proved that the Earth is like an orange.
James Jean described it as resembling a pear rather than an orange.
The outer surface of the earth can be divided mainly into 4 parts –
1. Lithosphere 2. Hydrosphere 3. Atmosphere 4. Biosphere
LITHOSPHERE
The entire outer layer of the Earth, on which the continents and oceans are located, is called lithosphere. Total 29% of the Earth is covered with land and 71% is covered with water. The ratio of Earth’s land area and water area is 3:7.
61% of the Earth’s Northern Hemisphere and 81% of the Southern Hemisphere’s area is covered by water.
The maximum height on Earth is Mount Everest (8,850 m) and the maximum depth is the Mariana Trench (11,022 m) *. Thus, there is a difference of about 20 km between the maximum height and maximum depth of the Earth.
Lithosphere is thicker (40 km) in continental areas and relatively thin (12-20 km) in oceanic areas
ROCK
The hard part of the earth’s surface is called rock, which are the basic units of the structure of the earth’s outer layer. On the basis of origin it is of three types-
1. Igneous rock: It is formed by the solidification of magma or lava. Like granite, basalt, pegmatite, diorite, grabo etc.
Igneous rock is thick layerless, hard compacted and fossil free. Economically it is a very prosperous rock. Magnetic iron, nickel, copper, lead, zinc, chromite, manganese, gold and platinum are found in it.
basalt has the highest amount of iron. Soil is formed from this rock.
Pegmatite: Mica found in Koderma (Jharkhand) is found in these rocks.
Igneous Rock Bodies Igneous Igneous, variation of rock Granite
Due to cooling of magma and taking solid form, various types of syenite, syenite and serpentine grabo cysts are formed. Igneous rock bodies are formed. They are named on the basis of their basalt shape, form, condition and the bituminous coal graphite rocks found nearby. Most rock bodies are formed from intrusive igneous rocks.
(a) Batholith: This is the largest igneous rock mass, which is formed from intrusive rocks. This is a hellish pin. It is in the shape of a large dome with steep sides. Its upper surface is uneven. It is made of free granite. idaho valley of the united states
It is spread over more than 40 thousand square kilometers. Canada’s coat range is larger than that of Beaulieu, Idaho.
(b) Stock: Small sized batholith is called stock. Its upper part is circular dome-shaped. The stock extends to less than 100 square km.
(c) Lacolith: When the magma forcefully rises up the upper layer and freezes in a dome-shaped form, it is called lacolith. Due to the rapid rising of magma, this dome-shaped solid mass appears umbrella-like. Many examples of laccoliths are found in the western part of North America.
Note: Lakolia is an intrusive counterpart of an extrusive volcanic mountain.
Lapolith: When the magma solidifies and takes a saucer-shaped shape, it is called Lapolith. Upoliths are found in South America.
(e) Phacolith: When magma solidifies in a grooved shape, it is called Phacolith.
(f) Sill: When magma spreads and freezes in layers parallel to the earth’s surface, it is called sill. Its thickness ranges from one meter to hundreds of meters. Sils are found in Chhattisgarh and Jharkhand. Cob less than one meter thick is called sheet.
(g) Dyke or Dike: When magma flows into a vertical cracks.
VALCANO
Volcano is a natural hole or crack in the earth’s crust. Through which the earth’s molten material like lava, ash, steam and other gases come out. The cup shaped mouth of the volcano is called Keter. The lava blown in the air soon cools down and turns into small solid pieces, which are called cinders. The percentage of vapor in the gases released during eruption is highest. According to the period of eruption, there are three types of volcanoes.
1. Active volcano: It erupts frequently. At present the number of active volcanoes in the world is 500. Prominent among these are Italy’s Etna and Stromboli. Colima Volcano located in Mexico (North America) is a very active volcano. It has been uttered more than 40 times.
Dormant volcano: In which the recent past
I have not uttered. But it can erupt at any time. There are examples. Vesuvius (Mediterranean Sea), Kakatova (Munda Strait), Fujiyama (Japan), Mewan (Philippines).
3. Extinct volcano: A volcano in which there has been no eruption since historical time and in which there is no possibility of eruption again. Its examples are-Koh Multan and Demvand (Iran), Popa (Myanmar), Kilimanjaro (Africa), Chimbrazo (South America)
Most of the few active volcanoes are found in the coastal part of the Pacific Ocean. The circumference of the Pacific Ocean is also called ‘Fire ring of the pacific’.
The most active volcanoes are located on the coasts of America and Asia.
There is not a single volcano in the Australian continent.
Geyser: At the time of eruption in many volcanic areas
Water and steam start rising to a higher height through the cracks and holes. This is called Geser. Like-Old Faithful Geiser, this U.S.A. Is in Yellowstone Park. It keeps on erupting every minute.
Fumaroles: Symbolize the final stage of volcanic activity. Gas and water vapor come out from them. The sulfur containing minerals are called solfatara. Katmai Mountain of Alaska (USA) is called A valley of ten thousand smokes. The Koh Sultan smokestack of Iran and the smokestack of White Island situated in the Bay of Plenty of New Zealand are also famous.
EARTHQUAK
A special branch of geology, in which earthquakes are studied, is called seismology. There are three types of vibrations in an earthquake. Are-
1. Primary or P. waves: This wave passes through every medium inside the Earth. Its average speed is 8 km per second. This speed is greater than all the waves, due to which these waves reach any place first. The path taken by these waves to pass through the earth is concave.
2. Secondary or S waves: These are also called transverse waves. This wave passes only through solid medium (average velocity 4 km per second).
3. Surface or L-waves: These are also called surface or long waves. These waves were discovered by H. D. Love. These are sometimes also called as love waves. Their other name is R-waves (Ray Light waves). These waves are mainly limited to the surface. It can pass through all three mediums, solid, liquid and gas. Its speed is 1.5-3 km per second. Surface waves are extremely destructive.
Seismic waves are recorded by an instrument called seismograph. From this the following facts emerge regarding their behaviour:
(a) The velocity of all seismic waves increases when passing through materials with greater density and decreases when passing through materials with less density.
(b) Only primary waves can pass through the central part of the Earth, but their velocity reduces there.
(c) Secondary waves cannot pass through liquids.
(d) L-waves travel only near the surface.
(e) These waves are reflected and refracted while passing through different mediums.