1982 年 35 巻 2 号 p. 171-181
Ten reservoir induced earthquakes were investigated. The relation between the dam height and the maximum magnitude of the induced earthquake was found. We show that there are the magnitude limit of earthquake related with the dam height. The Shenwo earthquake, this was only one exception of this relation, wasn't far from the 1975 Haicheng earthquake. It occurred only 43 days before the Haicheng earthquake. We think the Shenwo earthquake occurred in the precursory period of the Haicheng earthquake. So we concluded that it occurred under the special tectonic condition just before the large earthquake.
Fault plane solutions for reservoir induced earthquakes were also compared with those for natural ones. We got the result that the directions of P-axis and T-axis for induced earthquakes were not always same to those for natural ones. So, we concluded that induced earthquakes occurred in the faults which were weakened by the permeated water rather than in the faults which were easily dislocated by the tectonic force. Large aftershocks of the Xinfengjiang earthquake were investigated and we showed the examples of the shock induced by loading and unloading.
The b-values for the aftershocks of induced earthquakes were calculated, but we got only one b-value for natural one which could be compared to induced one and there was no significant difference between them.