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Richter scale Definition

☆ Rich·ter scale (rik′tər)

noun

a logarithmic scale for indicating the magnitude of earthquakes using data from a seismograph: each step represents a magnitude that is about 10 times greater than the preceding step, with 1 indicating a disturbance detectable only by instruments and 7 one that can cause major damage to buildings

Etymology: devised by C. Richter (1900-85), U.S. seismologist