We cannot directly observed earth's interior by mining and drilling, it is possible for few kilometers because of rapid increase in temperature. So some indirect observations are taken to known earths interior.
There are 3 layer of earth.
1. Crust
2. Mantle
3. Core
1. Crust: -
It is the outermost solid part of the earth. The thickness of the crust varies under the oceanic and continental areas. Oceanic crust is thinner as compared to the continental
crust. The mean thickness of oceanic crust is 5 km whereas that of the continental is around 30 km. The continental crust is thicker in the areas of major mountain systems. It is as much as 70 km thick in the Himalayan region. It is brittle (hard but breakable) in nature
About 98 per cent of the total crust of the earth is composed of eight elements like oxygen (46.60%), silicon (27.72%), aluminium (8.13%), iron(5%), calcium, sodium, potassium and magnesium, and the rest is constituted by titanium, hydrogen, phosphorous, manganese, sulphur, carbon, nickel and other elements. Most abundant material in earths crust is silicon (metalloid) and most abundant metal in earth's crust is aluminium.
2. Mantle: -
The Mohorovicic discontinuity, or "Moho", is the boundary between the crust and the mantle. The upper portion of the mantle is called asthenosphere. The word astheno means weak. It is considered to be extending up to 400km. It is the main source of magma that finds its way to the surface during volcanic eruptions. The crust and the uppermost part of the mantle are called lithosphere. It is in solid state.
3. Core: -
As indicated earlier, the earthquake wave velocities helped in understanding the existence of the core of the earth. The outer core is in liquid state while the inner core is in solid state. The core is made up of very heavy material mostly constituted by nickel and iron. It is sometimes referred to as the 'nife layer'.
There are 3 layer of earth.
1. Crust
2. Mantle
3. Core
1. Crust: -
It is the outermost solid part of the earth. The thickness of the crust varies under the oceanic and continental areas. Oceanic crust is thinner as compared to the continental
crust. The mean thickness of oceanic crust is 5 km whereas that of the continental is around 30 km. The continental crust is thicker in the areas of major mountain systems. It is as much as 70 km thick in the Himalayan region. It is brittle (hard but breakable) in nature
About 98 per cent of the total crust of the earth is composed of eight elements like oxygen (46.60%), silicon (27.72%), aluminium (8.13%), iron(5%), calcium, sodium, potassium and magnesium, and the rest is constituted by titanium, hydrogen, phosphorous, manganese, sulphur, carbon, nickel and other elements. Most abundant material in earths crust is silicon (metalloid) and most abundant metal in earth's crust is aluminium.
2. Mantle: -
The Mohorovicic discontinuity, or "Moho", is the boundary between the crust and the mantle. The upper portion of the mantle is called asthenosphere. The word astheno means weak. It is considered to be extending up to 400km. It is the main source of magma that finds its way to the surface during volcanic eruptions. The crust and the uppermost part of the mantle are called lithosphere. It is in solid state.
3. Core: -
As indicated earlier, the earthquake wave velocities helped in understanding the existence of the core of the earth. The outer core is in liquid state while the inner core is in solid state. The core is made up of very heavy material mostly constituted by nickel and iron. It is sometimes referred to as the 'nife layer'.
No comments:
Post a Comment