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In this article we are discussing our Earth.

Composition of Earth:

Earth was formed almost around 4500 million years ago.

Earth’s crust is made up of the following elements:

Iron (Fe)                  32%

Oxygen (O)              30%

Silicon (Si)               15%

Magnesium (Mg)       14%

Nickel (Ni)                2%

The trace amount of calcium, aluminium & other elements are also present in Earth’s crust.

The structure of Earth:

a) The structure of Earth is determined by seismic waves inside the Earth. 

b) When rock masses move deep within the Earth, energy in the form of seismic waves moves outward through the rock from the point of origin-called the focus. The initial movement occurs at the focus.

c) The epicenter is the point on the surface directly above the focus. From epicenter, seismic waves radiate in all directions on surface of the Earth.

Here are two different types of waves:

Body waves: These waves moves into internal layers of the Earth. Body waves are further divided into 2 parts:

The S waves help scientists to understand the interior of the Earth.

Surface waves: These waves move in the surface of Earth. These waves are responsible for creating vibration and shakes on the Earth’s surface. 

The S waves help scientists to understand the interior of the Earth.

Surface waves: These waves move in the surface of Earth. These waves are responsible for creating vibration and shakes on the Earth’s surface. 

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