Long-term earthquake prediction in the circum-pacific convergent belt

Investigation of the time-dependent seismicity in 274 seismogenic regions of the entire continental fracture system indicates that strong shallow earthquakes in each region exhibit short as well as intermediate term time clustering (duration extending to several years) which follow a power-law time distribution. Mainshocks, however (interevent times of the order of decades), show a quasiperiodic behaviour and follow the ʹregional time and magnitude predictable seismicity modelʹ. This model is expressed by the following formulas log T t = 0.19 M~n + 0.33 Mp - 0.39 log m 0 + q MU = 0.73 Mini n - 0.28 Mp + 0.40 log m 0 + m which relate the interevent time, Tt (in years), and the surface wave magnitude, My, of the following mainshock: with the magnitude, Mmin, of the smallest mainshock considered, the magnitude, Mp, of the preceded mainshock and the moment rate, m 0 (in dyn.cm.yr-1), in a seismogenic region. The values of the parameters q and m vary from area to area. The basic properties of this model are described and problems related to its physical significance are discussed. The first of these relations, in combination with the hypothesis that the ratio T/Tz, where T is the observed interevent time, follows a lognormal distribution, has been used to calculate the probability for the occurrence of the next very large mainshock (M s > 7.0) during the decade 1993-2002 in each of the 141 seismogenic regions in which the circum-Pacific convergent belt has been separated. The second of these relations has been used to estimate the magnitude of the expected mainshock in each of the regions.