Energy class based on an earthquake's seismic energy, although S. L. Solov'ev seems to have made major contributions. (In contrast to the "Richter" and other magnitude scales developed by Western seismologists, which estimate the magnitude from the amplitude of some portion of the seismic waves generated, an indirect measure of seismic energy.) However, proper estimation of E requires more sophisticated tools than were available at the time, and Bune's method was unworkable. A more practical revision was presented by T. G. Rautian in 1958 and 1960; by 1961 K-class was being used across the USSR. A key change was to estimate E
Richter magnitude scale distance of the station, formula_23. In practice, readings from all observing stations are averaged after adjustment with station-specific corrections to obtain the formula_2 value. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; in terms of energy, each whole number increase corresponds to an increase of about 31.6 times the amount of energy released, and each increase of 0.2 corresponds to approximately a doubling of the energy released. Events with magnitudes greater than 4.5 are strong enough to be recorded by a seismograph anywhere in the world, so