Project Java Webmaster: Glenn A. Richard
Mineral Physics Institute
SUNY Stony Brook
This applet illustrates the utilization of the arrival times of P and S waves at seismic stations to determine the location of earthquake epicenters. Since P waves travel through the shallow parts of Earth at about 8 kilometers per second, and S waves travel at about 5 kilometers per second, the P waves will arrive first at a seismic station after a quake occurs. In fact, the delay time between the arrival of the P waves and the arrival of the S waves increases with distance and can be used to compute the distance from the event.
The distance of the epicenter form each station can be repsresented by a circle of appropriate radius. With data from three or more stations, circles can be drawn on a map that intersect at the epicenter.
To generate a quake, and see the intersection of the circles representing distance, click the Earthquake button. The Details button reveals distances and time delay for each station. Click the Close button to dismiss this window. You can change the scale of the map by entering a number in the Scale field.
Source List for the Three Versions of Quake
Yevgevniy Miretskiy: eugene@invision.net
Mikhail Sabaev: sabaevm@ug.cs.sunysb.edu