GEOLOGY

Detailed explanation-1: -Seismic P waves are also called compressional or longitudinal waves, they compress and expand (oscillate) the ground back and forth in the direction of travel, like sound waves that move back and forth as the waves travel from source to receiver. P wave is the fastest wave.

Detailed explanation-2: -P waves are also known as compressional waves, because they push and pull. Particles subjected to a P wave move in the same direction that the wave is moves in; it is the direction that the energy is traveling in, sometimes called the “direction of wave propagation.”

Detailed explanation-3: -In P or compressional waves, the vibration of the rock is in the direction of propagation. P waves travel fastest and are the first to arrive from the earthquake. In S or shear waves, rock oscillates perpendicular to the direction of wave propagation.

Detailed explanation-4: -P waves cause the ground to compress and expand, that is, to move back and forth, in the direction of travel. They are called primary waves because they are the first type of wave to arrive at seismic recording stations. P waves can travel through solids, liquids, and even gases.