Graph of magnitude 5 or greater earthquakes from 1970- April 2011
The United States Geological Survey (USGS) keeps track of earthquake locations and magnitudes, accessible on the USGS website. Modern recording equipment has been in use since about 1900. While this may seem like long ago, this only provides a VERY short reliable earthquake record. This graph shows the magnitude of earthquakes (looking only at those greater than M = 5) versus time since 1970.