Charles Francis Richter developed a logarithmic scale to measure intensity. The name "magnitude" for this measurement came from Richter's childhood interest in astronomy - astronomers measure the intensity of stars in magnitudes. Gutenberg's contribution was substantial, but his aversion to interviews contributed to his name being left off the scale. After the publication of the proposed scale in 1935, seismologists quickly adopted it for use in measuring the intensity of earthquakes. Richter remained at the Carnegie Institute until 1936, when he obtained a post at the California Institute of Technology, where Beno Gutenberg worked. Gutenberg and Richter published "Seismicity of the Earth" in
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