GEOLOGY

Detailed explanation-1: -P-waves are the first waves to arrive on a complete record of ground shaking because they travel the fastest (their name derives from this fact-P is an abbreviation for primary, first wave to arrive). They typically travel at speeds between  1 and  14 km/sec.

Detailed explanation-2: -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-3: -The first of these are known as P waves, for primary or pressure. They are fast, traveling through rock at over 225 miles per hour (360 km/hr) and through water at about one-third that speed, pushing, pulling, and compressing the earth in the direction of their travel.

Detailed explanation-4: -The P–wave velocity increases smoothly with depth from 8.1 km/s at the outer rim to 10.3 km/s above the inner core boundary. The boundary between the inner and outer core is fairly sharp.