Charles Francis Richter (English pronunciation: /ˈɹɪktəɹ/, April 26, 1900 – September 30, 1985), was an American seismologist and physicist. Richter is most famous as the creator of the Richter magnitude scale which, until the development of the moment magnitude scale in 1979, quantified the size of earthquakes. Inspired by Kiyoo Wadati's 1928 paper on shallow and deep earthquakes, Richter first used the scale in 1935 after developing it in collaboration with Beno Gutenberg; both worked at California Institute of Technology, California, USA. The quote "logarithmic plots are a device of the devil" is attributed to Richter.

Charles was born in Hamilton, OH. His parents (Fred W. Kinsinger and Lillian Anna Richter) were divorced when he was very young. He grew up with his maternal grandfather, who moved the family (including his mother) to Los Angeles in 1909. He attended Stanford University and received his undergraduate degree in 1920. In 1928, he began work on his Ph.D. in theoretical physics from the California Institute of Technology (Caltech), but, before he finished it, he was offered a position at the Carnegie Institute of Washington. At this point, he became fascinated with seismology (the study of earthquakes and the waves they produce in the earth). Thereafter, he worked at the new Seismological Laboratory in Pasadena, under the direction of Beno Gutenberg. In 1932, Richter and Gutenberg developed a standard scale to measure the relative sizes of earthquake sources, called the Richter scale. In 1937, he returned to the California Institute of Technology, where he spent the rest of his career, eventually becoming professor of seismology in 1952.

Richter went to work at the Carnegie Institute in 1927 after receiving a job offer to be a research assistant there from Robert Millikan. Here he began a collaboration with Beno Gutenberg. The Seismology lab at the California Institute of Technology was hoping to begin publishing regular reports on earthquakes in southern California and had a pressing need to have a system of measuring the strength of earthquakes for these reports. Together, they had devised the scale that would become known at the Richter scale to fill this need, based on measuring quantitatively the displacement of the earth due to seismic waves, as had been suggested by Kiyoo Wadati. The pair designed a seismograph that measured this displacement, and developed a logarithmic scale to measure intensity. The name "magnitude" for this measurement came from Richter's childhood interest in Astronomy, where the intensity of stars is measured in magnitudes. Gutenberg's contribution was substantial, but his aversion to interviews contributed to his name being left off the scale. After publishing the proposed scale in 1935, it was quickly adopted for use in measuring the intensity of earthquakes.

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