Richter scale

A scale of numerical values, proposed by C. F. Richter, to describe the magnitude of an earthquake, ranging from 1 to 9, by measurements made in well-defined conditions and with a given type of seismograph. The zero of the scale is fixed arbitrarily to fit the smallest recorded earthquake. The largest recorded earthquake magnitudes are near 8.7. This is the result of observations and not an arbitrary upper limit like that of the intensity scale. For more information about the Richter Scale visit the U.S. Geological Survey National Earthquake Information Center.