Since the 1960s, seismologists have stopped using the famous Richter scale, preferring to use a moment magnitude scale, which ...

ß = (10 dB) log I/I o For this equation, I o is a reference intensity, chosen to be 10^-12 W/m^2 , approximately the threshold of human hearing at 1 kHz. If the intensity of a sound wave equals I o , ...

R. Schielen, A. Doelman, Modulation Equations for Spatially Periodic Systems: Derivation and Solutions, SIAM Journal on Applied Mathematics, Vol. 58, No. 6 (Dec ...