What is the Richter scale?

The Richter scale is a way of measuring the magnitude, or energy release, of an earthquake, developed by the American seismologist Charles Richter in 1935. It is logarithmic, so each whole number step represents a tenfold increase in the amplitude of the seismic waves and roughly 32 times more energy released: a magnitude 7 quake is far more destructive than a magnitude 6. Small quakes below about magnitude 3 are rarely felt, while great earthquakes above magnitude 8 can cause catastrophic damage. Modern seismologists mostly use a refined version called the moment magnitude scale, which works better for very large earthquakes, but the public still often calls it the Richter scale.