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: -S waves, which travel at about half the speed of P waves, arrive later. A seismic station close to the earthquake records P waves and S waves in quick succession. With increasing distance from the earthquake the time difference between the arrival of the P waves and the arrival of the S waves increases.

Detailed explanation-3: -P waves can travel through liquid and solids and gases, while S waves only travel through solids. Scientists use this information to help them determine the structure of Earth. For example, if an earthquake occurs on one side of Earth, seismometers around the globe can measure the resulting S and P waves.

Detailed explanation-4: -The greater the interval between the arrival of the first P wave and the first S wave, the greater the distance to the earthquake epicenter.

Detailed explanation-5: -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.