Fig. 5

(a) Statistical periodic upward migration (PUM) model for M ≥ 7.5 earthquakes, in which T _P = 100 years is shown as an example. (b) Superposed PUM model, in which the horizontal axis represents the year of each century. The hatched regions indicate high-seismicity periods. The symbols are the same as those used in Fig. 4. These are optimal solutions (Solutions 1 and 7 in Table 2) of the PUM model. F: Fake M 7 earthquakes shown in Table 1 (see text).