Charles Francis Richter an instrument generally consisting of a constantly unwinding roll of paper, anchored to a fixed place, and a pendulum or magnet suspended with a marking device above the roll, to record actual earth motion during an earthquake. The scale takes into account the instrument's distance from the epicenter, or the point on the ground that is directly above the earthquake's origin. Richter chose to use the term "magnitude" to describe an earthquake's strength because of his early interest in astronomy; stargazers use the word to describe the brightness of stars. Gutenberg suggested that the scale be logarithmic so an earthquake
Richter magnitude scale isolated area. Several scales have historically been described as the "Richter scale", especially the "local magnitude" formula_2 and the surface wave formula_3 scale. In addition, the "body wave magnitude", formula_4, and the "moment magnitude", formula_5, abbreviated MMS, have been widely used for decades. A couple of new techniques to measure magnitude are in the development stage by seismologists. All magnitude scales have been designed to give numerically similar results. This goal has been achieved well for formula_2, formula_3, and formula_5. The formula_4 scale gives somewhat different values than the other scales. The reason for so many different ways to measure