Question

the seismograph below records the arrival times of seismic waves at a station in portland. using the seismograph data provided, which of the following correctly identify the arrival times for the p and s waves? the p wave arrives at 120 seconds and the s wave arrives at 240 seconds. the p wave arrives at 0 seconds, and the s waves arrives at 60 seconds. the p wave arrives at 0 seconds, and the s wave arrives at 120 seconds. the p wave arrives at 60 seconds, and the s wave arrives at 180 seconds.

Explanation:

Step1: Analyze the seismograph

The first set of waves (P - waves) arrive at 0 seconds as they are the fastest.

Step2: Analyze the lag time

The lag time between P and S waves is 120 seconds. So S - waves arrive at \(0 + 120=120\) seconds.

Answer:

The P wave arrives at 0 seconds, and the S wave arrives at 120 seconds.