International Relations Prelims Question

Earthquake waves are basically of two types — body waves and surface waves.
Body waves are generated due to the release of energy at the focus and move in all directions, travelling through the body of the earth. Hence, the name body waves.
The body waves interact with the surface rocks and generate new set of waves, called surface waves. These waves move along the surface.
The velocity of the waves changes, as they travel through materials with different densities. The denser the material, the higher is the velocity.
Their direction also changes, as they reflect or refract when coming across materials with different densities.
There are two types of body waves. They are called P and S-waves. P-waves move faster and are the first to arrive at the surface. These are also called ‘primary waves’. The P-waves are similar to sound waves. They travel through gaseous, liquid and solid materials.
S-waves arrive at the surface with some time lag. These are called secondary waves. An important fact about S-waves is that they can travel only through solid materials.
The variations in the direction of waves are inferred with the help of their record on seismograph.
The surface waves are the last to report on seismograph. These waves are more destructive.

Earthquake waves are basically of two types — body waves and surface waves.
Body waves are generated due to the release of energy at the focus and move in all directions, travelling through the body of the earth. Hence, the name body waves.
The body waves interact with the surface rocks and generate new set of waves, called surface waves. These waves move along the surface.
The velocity of the waves changes, as they travel through materials with different densities. The denser the material, the higher is the velocity.
Their direction also changes, as they reflect or refract when coming across materials with different densities.
There are two types of body waves. They are called P and S-waves. P-waves move faster and are the first to arrive at the surface. These are also called ‘primary waves’. The P-waves are similar to sound waves. They travel through gaseous, liquid and solid materials.
S-waves arrive at the surface with some time lag. These are called secondary waves. An important fact about S-waves is that they can travel only through solid materials.
The variations in the direction of waves are inferred with the help of their record on seismograph.
The surface waves are the last to report on seismograph. These waves are more destructive.

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