Earthquakes & Epi-centers

To determine the epi-center of an earthquake we need to use 3 seismograph readings and subtract the time difference between the p and s wave.   Then use your ESRT to find the distance from the seismic station.    Use your compass to draw a circle around the seismic station according to each distance.  Triangulate the point by finding where the circles intersect for the exact epi-center.

Homework Problem-

The difference in arrival times for P- and S-waves from an

earthquake is 5.0 minutes. According to the Earth Science

Reference Tables, how far away is the epicenter of the

earthquake?

A) 2.6 x 103 km

B) 8.1 x 103 km

C) 3.5 x 103 km

D) 1.3 x 103 km