Charles Richter

Born on 26 April 1900 in Ohio, Charles Richter was a seismologist who developed the Richter scale for determining earthquake magnitude. Richter earned a bachelor’s in physics from Stanford University in 1920 and his PhD in theoretical physics from Caltech in 1928. Richter then went to work at the newly established Seismological Laboratory in Pasadena; he later became a seismology professor at Caltech. His decades-long collaboration with lab director Beno Gutenberg included the development in 1935 of the Richter scale as an improvement over the more subjective Mercalli scale, which classified earthquakes by the amount of damage to buildings and people. The Richter scale assigned earthquakes a magnitude number depending on the amount of ground motion as measured by seismometers. Richter based the scale on the logarithmic stellar magnitude scale used in astronomy. Besides measuring earthquakes, Richter worked hard to promote better building codes and earthquake preparedness and is credited with saving many lives. Richter also published two textbooks that have become standard references in the field: Seismicity of the Earth (1941), cowritten with Gutenberg, and Elementary Seismology (1958). After retiring from Caltech in 1970, he helped establish a seismic consulting firm. Richter died in 1985 at age 85.

Date in History: 26 April 1900