Question

Understand how the epicenter of an EQ is located using the S- and P-wave arrival times.

a) By measuring the time difference between S-waves and P-waves at a single location
b) By comparing the Richter scale and the Mercalli scale
c) By analyzing the composition of the Earth's crust
d) By studying the history of seismic activity in a region

Answer 1

Seismologists use the time difference between the arrival of P-waves and S-waves at a single location to locate the epicenter of an earthquake.

Step-by-step explanation:

Seismographs measure the arrival times of earthquakes with a precision of 0.100 s.

To determine the distance to the epicenter of an earthquake, seismologists compare the arrival times of P-waves and S-waves, which travel at different speeds. The time difference between the arrival of these waves at a single location is used to locate the epicenter. P-waves, also known as pressure waves, travel faster than S-waves, or shear waves, and therefore arrive at the seismograph station first.

By measuring the time difference between the two waves, seismologists can calculate the distance to the epicenter using a formula based on the difference in wave speeds.