Abstract :
This paper provides a generic equation for the evaluation of the maximum earthquake
magnitude mmax 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 mmax.
The three estimates of mmax 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 mmax is considered more reliable than the other two which
are based on the Gutenberg-Richter relation.
