Estimation of the maximum earthquake magnitude, mmax

This paper provides a generic equation for the evaluation of the maximum earthquake magnitude m(max) for a given seismogenic zone or entire region. The equation is capable of generating solutions in different forms, depending on the assumptions of the statistical distribution model and/or the available information regarding past seismicity. It includes the cases (i) when earthquake magnitudes are distributed according to the doubly-truncated Gutenberg-Richter relation, (ii) when the empirical magnitude distribution deviates moderately from the Gutenberg-Richter relation, and (iii) when no specific type of magnitude distribution is assumed. Both synthetic, Monte-Carlo simulated seismic event catalogues, and actual data from Southern California, are used to demonstrate the procedures given for the evaluation of m(max). The three estimates of m(max) for Southern California, obtained by the three procedures mentioned above, are respectively: 8.32 +/- 0.43, 8.31 +/- 0.42 and 8.34 +/- 0.45. All three estimates are nearly identical, although higher than the value 7.99 obtained by Field et al. (1999). In general, since the third procedure is non-parametric and does not require specification of the functional form of the magnitude distribution, its estimate of the maximum earthquake magnitude m(max) is considered more reliable than the other two which are based on the Gutenberg-Richter relation.