1. Distance from Epicenter
Name_____________________________ Date____________ Period_____
Station
S-P Interval
Amplitude
Distance from Epicenter
Las Vegas, NV #1
Busan, Japan
Phoenix, AZ
Elko, NV
Las Vegas, NV #2
Tokyo, Japan
Fresno, CA
Eureka, CA

2. Measuring the S-P Interval
In order to locate the epicenter of an earthquake, you need to estimate the time interval between the arrival of the P and S waves (S-P interval) on the seismograms from three different stations.
You have to measure the interval to the closest second and then use a graph to convert the S-P interval to the epicentral distance.
On the sample to the right, the vertical lines are spaced at 2 second intervals and the S-P interval time is about 36 seconds.
The amplitude is then used to determine the magnitude of the earthquake.
The Amplitude is determined by measuring the highest peak of the S-wave starting from zero millimeter.
From the sample to the right, the height of the amplitude is 160mm

4. Seismic Station— Las Vegas, NV #1

5. Seismic Station—Busan, Japan

6. Seismic Station—Phoenix, AZ

7. Seismic Station— Elko, NV

8. Seismic Station—Las Vegas, NV #2

9. Seismic station—Tokyo, Japan

10. Seismic Station—Fresno, CA

11. Seismic Station— Eureka, CA