Moment magnitude scale released, and an increase of two steps corresponds to a 10 (1,000) times increase in energy. Thus, an earthquake of "M" of 7.0 releases about 32 times as much energy as one of 6.0 and nearly 1,000 times one of 5.0. The moment magnitude is based on the seismic moment of the earthquake, which is equal to the shear modulus of the rock near the fault multiplied by the average amount of slip on the fault and the size of the area that slipped. Since January 2002, the MMS has been the scale used by the United States Geological Survey
Order of magnitude An order-of-magnitude difference between two values is a factor of 10. For example, the mass of the planet Saturn is 95 times that of Earth, so Saturn is "two orders of magnitude" more massive than Earth. Order-of-magnitude differences are called decades when measured on a logarithmic scale. Other orders of magnitude may be calculated using bases other than 10. The ancient Greeks ranked the nighttime brightness of celestial bodies by 6 levels in which each level was the fifth root of one hundred (about 2.512) as bright as the nearest weaker level of brightness, and thus the brightest level being