Internal Structure Of Earth

Geophysics, the study of the physics of the earth, led to many important discoveries about the earth and its composition. Seismic studies of the Earth, have revealed new information about Earth's interior, which helped invent the theory of plate tectonics.
Geophysical investigations have brought to light that the Earth has a number of layers. Each of these layers has its own characteristics. The outer layer of the earth's surface. It includes the continents and made the sea. The crust has a variable thickness, with 35-70 km of thick dick in the world and 50-10 km in the sea. The surface consists mainly of alumina-silicates.
The next layer is the mantle, mainly of silicates of magnesium, iron compound. It is about 2900 km thick and is divided into upper and lower mantle. This is where most of the internal heat of the earth is located. Large convection cells of the mantle circulate heat and power rhythm of the earth.

The last layer is the core in the liquid outer core is separated and the solid inner core. The outer core is 2300 km thick and the inner core is 1200 km thick. The outer core is mainly an alloy of nickel-iron, while the inner core consists almost entirely of iron. Earth's magnetic field is assumed to be controlled by the liquid outer core.
The country is divided into layers on the mechanical properties and composition. The top layer is the lithosphere, the solid component of the earth's crust and upper mantle exists. The lithosphere is divided into several plates move towards each other, divided by tectonic forces. The lithosphere essentially floats above numbers on a semi-liquid layer as the asthenosphere. This layer allows the solid earth's crust move from the asthenosphere is much weaker than the lithosphere.