Question

How do you determine the difference in time between the arrival of the primary (p) wave and the arrival of the secondary (s) wave during an earthquake? (in other words, how do you determine t?)add the s and p wavessubtract the s from the p wavesubtract the p from the s wavemultiply the s and the p waves

Answer 1

Correct answer: Subtract the p from the s

The study of earthquake is known as seismology, it study its effect and waves form. The two seismic waves studied in earthquake are P wave and S wave. P-wave is known as primary wave and S-wave is known as secondary wave.

P-wave are fastest wave and it travels through solid, liquid and gas. S-wave are slower as compared to p-wave and are second to arrive, it could pass only through solid and could not pass through liquid and gas. They travel in perpendicular direction to the vibration of the particles.

Example: Suppose the P-wave arrives at t = 1.0 s and the S-wave arrives at t = 6.0 s, then the difference between the arrival time of the P-wave and the S-wave can be calculated as:

Time Difference = 6.0 −1.0=5.0 s

Answer 2

The correct answer is option Subtract the P wave from the S wave.

In a seismographic centre, there are two types of waves, which are recorded, these are the P and the S waves. The P waves are the primary waves and travel fast, and the S wave is the secondary wave travels slow. The time of the approaching of the S wave increases as the as distance from the epicentre increases. The time lag between the P and the S wave determines the t. So, it can be recorded by subtracting the time of the arrival of the P wave from the timing of the arrival of the S wave.