Building and Using Lehman Seismometers

Abstract

Seismometers are used to detect vibrations in the earth. They can be made extremely sensitive even with very simple and inexpensive parts. The most basic seismometers behave like horizontal pendulums, which are caused to swing when the earth undergoes small movements. The swinging motion is made to produce a tiny current, which we detect and record using a micro-controller. A few seismometers separated geographically allow one to triangulate to the location of the earthquake. We have built a few Lehman seismometers which we are currently testing and calibrating. We can now detect earthquakes as low as 2.5 on the Richter scale anywhere in Oklahoma.