GEOLOGY

Detailed explanation-1: -As the P and S waves travel out from an earthquake the P waves get progressively farther ahead of the S waves. Therefore, the farther a seismic recording station is from the earthquake epicenter the greater will be the difference in time of arrival between the P and S wave.

Detailed explanation-2: -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-3: -The P waves are easy to identify because they are always first to arrive and their amplitude is smaller than the S wave. S waves are indicated by an abrupt change in wave amplitude. In the seismogram below, we see that the S wave arrived at about 34 sec after the P wave arrived.

Detailed explanation-4: -Earthquake waves diminish in intensity as they travel through the ground, so earthquake shaking is less intense farther from the fault. Low-frequency waves diminish less rapidly with distance than do high-frequency waves.

Detailed explanation-5: -Surface waves attenuate where they are strongest near the epicenter and dissipate as you move farther away.