Fig. 2.
(a) Temporal change in b-value and Mc in the whole study area. Mc is the magnitude of completeness, which is calculated every year. The time window for calculating the b-value is five years long and earthquakes with M ≥ 4.5 are used. For example a b-value plotted at the year of 1990 is calculated by using earthquakes which occurred from 1985 to 1990. (b) Distribution of Zmax, obtained by a numerical simulation assuming that earthquakes occur randomly in space and time. 500 synthetic earthquake catalogs are produced by UNIX commands.