Charles Francis Richter heart failure on September 30, 1985 in Pasadena, California. He is buried in Altadena, California's Mountain View Cemetery and Mausoleum. Charles Francis Richter Charles Francis Richter (); 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 the California Institute
Moment magnitude scale band. To simplify this calculation, he noted that the lowest frequency parts of the spectrum can often be used to estimate the rest of the spectrum. The lowest frequency asymptote of a seismic spectrum is characterized by the seismic moment, . Using an approximate relation between radiated energy and seismic moment (which assumes stress drop is complete and ignores fracture energy), (where E is in Joules and is in Nformula_4m), Kanamori approximated by The formula above made it much easier to estimate the energy-based magnitude , but it changed the fundamental nature of the scale into a moment magnitude scale.