18. Suppose an earthquake has just occurred. Seismic waves from the earthquake are detected

Question

at 2 different recording stations. At Recording Station A, the time difference At = 60 s. At
Recording Station B At = 100 s. Which recording station is farther away from the epicenter?
(1 point)
• A. Station A is farther from the epicenter than Station B.
• B. Station B is farther from the epicenter than Station A.
• C. Stations A and B are the same distance from the epicenter.
• D. It cannot be determined.

Answer 1

The time difference, Δt, between the arrival of seismic waves at different recording stations can be used to determine their distance from the epicenter of the earthquake. Generally, the greater the time difference between the arrival of the primary (P) and secondary (S) waves at a station, the farther that station is from the epicenter.

In this case:

• At Recording Station A, Δt = 60 s
• At Recording Station B, Δt = 100 s

Since the time difference at Station B is greater than that at Station A, it implies that Station B is farther from the epicenter.

Therefore, the correct answer is:

B. Station B is farther from the epicenter than Station A.