1. GY111L Physical Geology Lab
Calculating epicenter position from seismic data.

2. Using the following graphs calculate the epicentral distance of the seismic event from Mobile (already done as an example), Pensacola, and Montgomery. Fill in the provided Epicentral Distance table provided below:
Plot the position of the epicenter on the provided map below. What is the closest town/city to the epicenter of the seismic event? _________________________________
Estimate the actual time of the seismic event: __________________ (Hint: the answer can be calculated from the Seismic Wave Travel Time graph).
City
Epicentral Distance
Mobile
90 km
Pensacola
Montgomery

3. Seismic Wave Data
Mobile
13:55:40
13:55:50
P-wave
S-wave
dT=13:55:50-13:55:40=10.0s
13:55:45
13:56:03
Pensacola
dT=________________
13:56:17.5
13:56:44
Montgomery
dT=________________
13:55
13:56
Time
13:57
13:58

4. Seismic Wave Travel Time vs. Epicenter Distance
500
400
Distance from epicenter (km)
300
P-wave
200
S-wave
100
10s
90km 10 20 30 40 50 60 70 80
Travel Time (seconds)

5. Epicentral Distance Table
Station
Ts-Tp dT
Epicentral Distance (km)
Mobile
13:55:50.0-
13:55:40.0
10 seconds
90.0
Pensacola
Montgomery