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Earthquake Size as a Function of Fault Slip Rate

John G. Anderson, Steven G. Wesnousky, & Mark W. Stirling

Published June 1996, SCEC Contribution #244

Estimates of the potential size of earthquakes on mapped active faults are generally based on regressions of earthquake magnitude (Mw) versus length (L ) of fault rupture for historical earthquakes. The fault slip rate (S ) has been ignored in formal prediction equations, but more accurate predictions of future earthquake magnitudes on mapped faults may be obtained when it is included. A least squares regression for a data set of 43 earthquakes occurring on faults for which slip rates are reported shows Mw= 5.12+ 1.l6 log L - 0.20logS ,where L is in units of kilometers and S is in units of mm/yr. The result indicates that the largest earthquakes will occur on the slowest slipping faults if the rupture length is held constant.

Key Words
magnitude, slip rates, risk assessment, earthquakes, faults, earthquake prediction

Anderson, J. G., Wesnousky, S. G., & Stirling, M. W. (1996). Earthquake Size as a Function of Fault Slip Rate. Bulletin of the Seismological Society of America, 86(3), 683-690.