Richter magnitude scale retain the logarithmic character of the original, and are scaled to have roughly comparable numeric values. Prior to the development of the magnitude scale the only measure of an earthquake's strength or "size" was a subjective assessment of the intensity of shaking observed near the epicenter of the earthquake, categorized by various seismic intensity scales such as the Rossi-Forel scale. In 1883 John Milne surmised that the shaking of large earthquakes might generate waves detectable around the globe, and in 1899 E. Von Rehbur Paschvitz observed in Germany seismic waves attributable to an earthquake in Tokyo. In the 1920s Harry
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