Seismic risk of circum-pacific earthquakes I. Strain energy release

Abstract

Commonly used earthquake "whole process" frequency - magnitude and strain energy - magnitude laws are merged to obtain an analytic expression for an upper bound magnitude to regional earthquake occurrence M3, which is expressed primarily in terms of the annual maximum magnitude M1 and the magnitude equivalent of the annual average total strain energy release M2. Values of M3 are also estimated graphically from cumulative strain energy release diagrams. Both methods are illustrated by application to the high seismicity of the circum-Pacific belt, using Duda's (1965) data and regionalisation. Values of M3 obtained analytically, with their uncertainties, are in agreement with those obtained graphically. Empirical relations are then obtained between M1, M2, and M3, which could be of general assistance in regional seismic risk considerations if they are found to be of a universal nature. For instance. M3 and M2 differ by one magnitude unit in subregions of the circum-Pacific. © 1983 Birkhäuser Verlag