Surface-Wave Magnitude (Ms)
Surface-Wave Magnitude (Ms) :
An earthquake magnitude scale determined from surface wave records and introduced by Gutenberg (1945) uses maximum amplitudes of surface waves with periods around 20 seconds. In its IASPEI recommended standard form it is now termed Ms_20, uses a slightly different magnitude calibration function then Gutenberg and amplitude readings on seismic records which simulate the long-period WWSSN response. Another IASPEI recommended surface wave magnitude standard is the broadband version Ms_BB. It allows magnitude determinations in a wider range of periods (2 to 60 s) and distances (20 to 1600), is better tuned to the use of the IASPEI Ms standard calibration function and correlates better with the moment magnitude Mw. See magnitude saturation, Chapters 3 and IS 3.3 in this Manual, Bormann et al. (2009), and IASPEI (2011)
