Who invented the Richter scale to measure the magnitude of earthquakes?

Charles F. Richter of the California Institute of Technology developed the Richter scale in 1935 as a mathematical device to compare the sizes of earthquakes.

Each whole number increase in the scale corresponds to a tenfold increase in the amplitude of waves measured by a seismograph, or an increase of about 31 times the energy of a quake that is one number smaller.