GEOLOGY

Detailed explanation-1: -By measuring the time interval between the arrivals of the P and S wave groups seismologists are able to calculate the distance between the seismograph and the origin of the earthquake. Magnitude is then derived from the amplitude of the waves on the seismogram and the distance of the earthquake from the seismograph.

Detailed explanation-2: -Find difference in arrival time between P-wave and S-wave at the given epicenter distance, Subtract the difference in arrival time from the clock time of the S-wave.

Detailed explanation-3: -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. This time difference is called the S-P interval and is the lag time between the P and S wave.

Detailed explanation-4: -Scientists use triangulation to find the epicenter of an earthquake. When seismic data is collected from at least three different locations, it can be used to determine the epicenter by where it intersects. Every earthquake is recorded on numerous seismographs located in different directions.