GEOLOGY

Detailed explanation-1: -P Waves. The first kind of body wave is the P wave or primary wave. It’s the fastest kind of seismic wave, and the first to arrive at a seismic station. P waves can move through solid rock and fluids, like water or the liquid layers of the Earth.

Detailed explanation-2: -Body waves are of two types: Primary waves (also called P-waves, or pressure waves) and Secondary waves (S-waves, or shear waves). P-waves are compression waves. They can propagate in solid or liquid material. S-waves are shear waves.

Detailed explanation-3: -Why do P waves arrive first? When an earthquake occurs, seismic waves, including P and S waves carry energy away from the hypocenter in all directions. The P wave propagates with a velocity of about six kilometers per second in rock, while the S wave is slower at four kilometers per second.

Detailed explanation-4: -Generally, p-wave velocity increases with depth and increases with increasing rigidity of a material. Therefore p-waves travel fastest through the solid, iron inner core of Earth.

Detailed explanation-5: -In air, P waves take the form of sound waves and therefore move at the speed of sound, 330m/s at sea level.