GEOLOGY

Detailed explanation-1: -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. In rock, S waves generally travel about 60% the speed of P waves, and the S wave always arrives after the P wave.

Detailed explanation-2: -P-waves, or primary waves, are the fastest moving type of wave and the first detected by seismographs. They are also called compressional or longitudinal waves, and push and pull the ground in the direction the wave is traveling.

Detailed explanation-3: -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.

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: -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.