SOUNDS OF SEISMOLOGY:
What is the magnitude of an earthquake ?

The Richter scale is one of several measures of the size or "magnitude" of an earthquake. Earthquakes have a property (common to many natural processes) that there are many small ones and few large ones, referred to as the Gutenberg-Richter Law.



Although "magnitude" is related to the amplitude (height) of a wave, we cannot communicate the concept of magnitude using sound by changing the volume of the sound, in part because our speakers do not have much dynamic range. So instead of volume, we explain the meaning of magnitude by the duration that the Earth is shaking after an earthquake. We use several earthquakes from the region of Sumatra to illustrate these differences.