Layers of the Earth
Asthenosphere
The Asthenosphere is the zone which lies directly below the lithosphere. The asthenosphere is part of the upper mantle along. It is a thin layer, being around 80 to 200 km thick. However, the thickness can vary depending on its temperature. The lower boundary of the asthenosphere is not well defined.
Gutenberg discontinuity
The Gutenberg discontinuity occurs within Earth's interior at a depth of about 2,900 km (1,800 mi) below the surface, where there is an abrupt change in the seismic waves (generated by earthquakes or explosions) that travel through Earth. At this depth, primary seismic waves (P waves) decrease in velocity while secondary seismic waves (S waves) disappear completely.
Lehmann discontinuity
The Lehmann discontinuity is an abrupt increase of P-wave and S-wave velocities at the depth of 220±30 km, discovered by seismologist Inge Lehmann. It appears beneath continents, but not usually beneath oceans
Moho discontinuity
The Mohorovicic Discontinuity, or "Moho", is the boundary between the crust and the mantle. The red line in the drawing at right shows its location. In geology the word "discontinuity" is used for a surface at which seismic waves change velocity.
Continental crust
The continental crust is under continents and is between 8-75 km thick, but averages around 40 km thick. The continental crust consists of many rock types, but mainly granitic rocks such as granodiorite. The rocks in the continental crust are about 4 billions years old. The average density of the continental crust is about 2.7 g/m.
What is the longest tunnel inside the earth we have ever built?
The distance to the center of the Earth is 6,371 kilometers (3,958 mi), the crust is 35 kilometers (21 mi) thick, the mantle is 2855km (1774 mi) thick — and get this: the deepest we have ever drilled is the Kola Superdeep Borehole, which is just 12km deep.
Inner core
The inner core is extremely hot. It is around 5730 degrees celsius. The inner core is shaped like a sphere having a radius of 1220 km. Although the inner core has an extremely high temperature it is compressed into a solid state by the great pressure
Lower mantle
The lower mantle is 660 km deep. Near the base of the mantle lies a more rigid layer called the lower mantle. Despite the rocks strength the rocks in the lower mantle are very hot and capable of gradual flow. The hundred feet above the core (in the mantle) often has softer, flowing rocks than that of the asthenosphere.
Mantle
The mantle is 2890 km thick, however it contains 82% of the Earth's volume. It is right below the crust.
Oceanic crust
The oceanic crust is below the ocean, and is very thin. It is the part of the Earth's crust that makes up the seafloor. The average thickness of the oceanic crust is around 7 km thick. It is mainly composed of igneous rocks, basalt and gabbro, a plutonic rock of crystalline texture.
Outer core
The outer core is around 2260 and is a liquid layer. The magnetic field is formed in this zone by the flow of metallic iron. The temperature of the outer core is sometimes 4030 degrees celsius
Mesosphere
The region of the earth's atmosphere above the stratosphere and below the thermosphere, between about 30 and 50 miles (50 and 80 km) in altitude. The mesosphere layer protects the planet Earth from the celestial rocky masses that enters the atmospheric envelope of the Earth , where they burn as a result of their friction with the air molecules , And forming luminous meteors .
Lithosphere
The solid outer section of the Earth, which includes the Earth's crust and upper mantle. The lithosphere averages around 100 km thickness.
What is the relation of tectonic plates to the layers of the earth?
The tectonic plates are in the crust and can push it up to fore mountains. They tectonic plates are also impacted by the heat of the layers.
Upper mantle
The upper mantle extends from the crust to a depth of 660 km, and is mostly solid. However, it is more malleable in regions from tectonic activity. In the upper crust there are two subdivisions, the lithosphere and the asthenosphere.
How do we know about the layers of the Earth?
We know about the layers of the Earth by study seismic waves and seeing how the P and S waves refract. One example is we know the outer core is liquid because S waves cannot travel through it, because S waves cannot travel through liquid.
