|Richter scale (ˈrɪxtə)|
|Compare Mercalli scale See also magnitude a scale for expressing the magnitude of an earthquake in terms of the logarithm of the amplitude of the ground wave; values range from 0 to over 9|
|[C20: named after Charles Richter (1900--85) US seismologist]|
|Richter scale (rĭk'tər) Pronunciation Key
A logarithmic scale used to rate the strength or total energy of earthquakes. The scale has no upper limit but usually ranges from 1 to 9. Because it is logarithmic, an earthquake rated as 5 is ten times as powerful as one rated as 4. An earthquake with a magnitude of 1 is detectable only by seismographs; one with a magnitude of 7 is a major earthquake. The Richter scale is named after the American seismologist Charles Francis Richter (1900-1985). See Note at earthquake.
A scale used to rate the intensity of earthquakes. The scale is open-ended, with each succeeding level representing ten times as much energy as the last. A serious earthquake might rate six to eight, and very destructive quakes rate higher.
Note: No quake greater than nine has ever been recorded.