GEOLOGY

Detailed explanation-1: -Earthquakes generate compressional waves (p-waves) and shear waves (s-waves). Compared to the speed of shear waves in a given earth material, the speed of compressional waves is the fastest. Because of this the compressional waves are the first waves to arrive on a complete record of ground shaking.

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: -When an earthquake occurs, seismic waves, including P and S waves carry energy away from the hypocenter in all directions. 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-4: -P waves, or primary waves, arrive first while S waves, or secondary waves, arrive second. Both waves cause the ground to shake when an earthquake occurs.

Detailed explanation-5: -Scientists discovered that Earth’s outer core is liquid by observing seismic waves. P waves travel through solid and liquid, but S waves do not travel through liquid.