Charles Francis Richter in southern California. Since 1935, several other magnitude scales have been developed. Richter was an active and avowed naturist. He travelled to many nudist communities with his wife. At his retirement party, a group of colleagues at Caltech, called the "Quidnuncs," played and sang a ditty titled "Richter Scale," which gave examples of earthquakes in American history, told in ballad style. Richter was not amused, however; he was furious. The author of the song, Kent Clark, stated in a 1989 interview that Richter enjoyed the song. The song is played on the Dr. Demento show occasionally. Richter died of congestive
Richter magnitude scale used by astronomers. Second, he wanted a magnitude of zero to be around the limit of human perceptibility. Third, he specified the Wood-Anderson seismograph as the standard instrument for producing seismograms. Magnitude was then defined as "the logarithm of the maximum trace amplitude, expressed in microns", measured at a distance of 100 km. The scale was calibrated by defining a magnitude 3 shock as one that produces (at a distance of 100 km) a maximum amplitude of 1 micron (1 µm, or 0.001 millimeters) on a seismogram recorded by a Wood-Anderson torsion seismograph. Finally, Richter calculated a table of distance