<P> The Richter magnitude scale ( M , also Richter scale ) assigns a magnitude number to quantify the size of an earthquake . The Richter scale , developed in the 1930s by Charles Francis Richter , is a base - 10 logarithmic scale in order to cover the huge range of earthquakes . It defines magnitude as the logarithm of the ratio of the amplitude of the seismic waves to an arbitrary , minor amplitude , as recorded on a standardized seismograph at a standard distance . </P>
describe what is meant by the magnitude of an earthquake
the logarithm of the ratio of the amplitude of the seismic waves to an arbitrary , minor amplitude , as recorded on a standardized seismograph at a standard distance