Charles Francis Richter and the development of seismic magnitude scale

Charles F. Richter, Father of Modern Seismology

Charles Francis Richter was an American seismologist and physicist. Richter is probably most well-known for having developed the Richter Magnitude Scale, which was utilized to measure the intensity of earthquakes. The Richter Magnitude Scale was the standard for seismic measurement until the development of the moment magnitude scale in 1979. Additionally, Richter wrote two seismology books that still provide valuable information to the field of seismology. Richter's contribution to the field of seismology helped propel the discipline and establish a better understanding of seismic activity in the world.

Richter was born in Hamilton, Ohio on April 26, 1900 and subsequently moved to Los Angeles, California in 1909. While in Los Angeles, he attended a preparatory school that was affiliated with the University of Southern California. Richter attended the University of Southern California during his freshman year later transferring to Stanford University where he was awarded a Bachelor of Arts in physics ("Richter, Charles F. (1900-1985)"). Richter would later earn his Ph.D. In theoretical physics from the California Institute of Technology (Cal Tech). It was also during this time that Richter was offered a position by Nobel-prize winning physicist, Robert A. Millikan, at Cal Tech's newly established Seismological Laboratory in Pasadena, California ("Richter, Charles F. (1900-1985)").

While at Cal Tech, Richter began to collaborate with Beno Gutenberg who would aid in the development of the Richter Magnitude Scale. In order to successfully develop a seismological measurement scale, the duo needed to be able to record and catalog several earthquakes a year. Prior to the development of the Richter Magnitude Scale, seismic activity was measured on the outdated Mercalli scale which measured the magnitude of a tremor based on the movements that could be felt or seen within a building ("Richter, Charles F. (1900-1985)"). The Richter Magnitude Scale looked beyond the effect that tremors had on buildings and measured the magnitude of the tremors caused by seismic activity. Since tremors range in magnitude, Richter recorded information based upon a logarithmic scale that was calibrated to the tremors produced in Southern California (Park). While modern seismographic machines record data electronically, the first seismic activities recorded utilized a pen attached to a string hung above a cylindrical drum. Seismic activity was then calculated by measuring the pen's swing in millimeters, taking its logarithm, and applying a correction for the distance between station and earthquake (Park).