Popis: |
A. Okada insists that the Median Tectonic Line is right-lateral strike-slip fault and destructive earthquakes have occurred cyclic in late Quaternary. He discovered the traces of earthquake in the late middle ages at Kamigirai, Ichiba-cho, in a stratum.But by presize study of trench and archaelogical excavation, existence of destructive earthquake is doubtful. And the curves in the path through rice fields are merely outward, appearance. A. Okada estimated an average slip rate at 6m/1OOOy in Holocene epoch from offset of terrace scarps.But geological compositions of two terrace correlated as same age are different each other from boring data and observation of outcrops.It may be thought that vertical displacement of Chichio fault at Kamigirai corresponds to tilting of Yoshino-gawa plain in middle or late Pleistocene. |