How to Locate Epicenters

Abstract

Earthquake location is one of the most basic and important activities in seismology. Hypocentral location is a complex topic that involves technical difficulties such as the reliability of absolute time at seismographs, observational difficulties such as the picking of arrival times, and theoretical difficulties such as error estimates in nonlinear inverse theory. Even so, earthquake location is such a fundamental topic that we want students to do exercises in epicenter location. While there are many resources available for the ( S-P ) method of epicentral determination, this column discusses a new addition to the EduQuakes online lab manual which shows students how to use just P waves to locate an epicenter. The classic earthquake location method found in nearly all introductory seismology books is the ( S-P ) method. The simplest case is for local earthquake location where the epicenter-to-station distances are less than two hundred kilometers, hypocentral depth is less than 15 kin, and we already know the crustal P …