Fig. 7

Coseismic slip distributions of Nankai Trough earthquakes occurred in shaded duration of Fig. 6. Large and small Nankai Trough earthquakes occur alternately, and the interval of the seismic cycle preceding the larger Nankai Trough earthquake is shorter than that preceding the smaller earthquake. In small earthquakes at the beginning of the first cycle (i.e., (a) and (b)) and the end of the second cycle (i.e., (d) and (e)), the eastern and western segments of the Nankai Trough rupture separately with time lags of about 2 days and 10 h, respectively. In contrast, large earthquakes in (c) and (f) break the entire region from western Shikoku to the Tokai region almost simultaneously