Question

P and S waves from an earthquake travel at different speeds, and this difference helps in locating the earthquake “epicenter” (where the disturbance took place).

(A) If an earthquake occurs and these two waves arrive at a particular seismic station with the P wave 2.0 min ahead of the S wave, then how far away was the earthquake? Assume typical speeds of 8.5 km/s and 5.5 km/s for P and S waves, respectively.

For part A i found 1.9 x 10^3 km

(B) If the seismic station can determine the distance of the epicenter from the seismic station, then how many seismic stations are needed to locate the epicenter? (Hint: GPS works in essentially the same manner)

Select one answer:

a. At least three seismic stations are needed.

b. At least four seismic stations are needed.

c. Only one seismic stations is needed.

d. At least two seismic stations are needed.

Answer 1