GEOLOGY

Detailed explanation-1: -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.

Detailed explanation-2: -The direct P wave arrives first because its path is through the higher speed, dense rocks deeper in the earth. The PP (one bounce) and PPP (two bounces) waves travel more slowly than the direct P because they pass through shallower, lower velocity rocks. The different S waves arrive after the P waves.

Detailed explanation-3: -A P body wave (primary body wave) is a compressional (longitudinal) wave that induces the particles in the rock to vibrate back and forth in the same direction the wave moves.

Detailed explanation-4: -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-5: -A P wave is a sound wave traveling through rock. In a P wave, the rock particles are alternately squished together and pulled apart (called compressions and dilatations), so P waves are also called compressional waves. These waves can travel through solids, liquids, and gases.