<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <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> <P> As measured with a seismometer, an earthquake that registers 5.0 on the Richter scale has a shaking amplitude 10 times greater than an earthquake that registered 4.0 at the same distance . As energy release is generally proportional to the shaking amplitude raised to the ​ ⁄ power, an increase of 1 magnitude corresponds to a release of energy 31.6 times that released by the lesser earthquake . This means that, for instance, an earthquake of magnitude 5 releases 31.6 times as much energy as an earthquake of magnitude 4 . </P>

Describe what is meant by the magnitude of an earthquake