The velocity of the transverse waves produced by an earthquake is 8.9 km/s, and that of the longitudinal waves is 5.1 km/s. A seismograph records the arrival of the transverse waves 68 s before the.

Question

The velocity of the transverse waves produced by an earthquake is 8.9 km/s, and that of the longitudinal waves is 5.1 km/s. A seismograph records the arrival of the transverse waves 68 s before the arrival of the longitudinal waves. How far away is the earthquake?

Please show work

Thank you!

Answer 1

Bruce

This is more a logical math question.

Suppose the earthquake is x km away.

Then the transverse waves will arrive in x / 8.9 seconds

and the longitudinal waves will arrive in x / 5.1 seconds

Obviously (x / 5.1) - (x/ 8.9) = 68

From this you can find x.

x ( 1/5.1 - 1/8.9) = 68, so x = 812.2 km (check it yourself as an exercise)

Then check the answer by calculating the time taken for the two forms of waves to arrive, and check the difference in times is approx 68s.

Mike