Charles Francis Richter

Charles Francis Richter was an American seismologist and physicist who spent his career at the California Institute of Technology. Inspired by Kiyoo Wadati's 1928 paper on shallow and deep earthquakes, he developed a logarithmic scale in collaboration with Beno Gutenberg and first used it in 1935. The Richter scale became the dominant tool for quantifying earthquake size worldwide until the moment magnitude scale replaced it in 1979. He died September 30, 1985, forty-four years after the scale made his surname a unit of measure.