GEOLOGY

Detailed explanation-1: -Both P and S waves travel outward from an earthquake focus inside the earth. The waves are often seen as separate arrivals recorded on seismographs at large distances from the earthquake. The direct P wave arrives first because its path is through the higher speed, dense rocks deeper in the earth.

Detailed explanation-2: -During an earthquake, vibrations called seismic waves move out from the focus in all directions. Seismic waves carry the energy of an earthquake away from the focus, through Earth’s interior, and across the surface.

Detailed explanation-3: -The focus is the place inside Earth’s crust where an earthquake originates. The point on the Earth’s surface directly above the focus is the epicenter. When energy is released at the focus, seismic waves travel outward from that point in all directions.

Detailed explanation-4: -An earthquake radiates P and S waves in all directions and the interaction of the P and S waves with Earth’s surface and shallow structure produces surface waves. Near an earthquake the shaking is large and dominated by shear-waves and short-period surface waves.

Detailed explanation-5: -As seismic waves travel away from the focus they decrease in energy & intensity. Why does the most damage occur close to the fault? The most damage occurs close to the fault because it is where the greatest amount of energy is found.