駿河湾西岸における活構造線 (帯) 存在の可能性
1984 年 37 巻 3 号 p. 453-464
詳細
1984 年 37 巻 3 号 p. 453-464
The possibility of the existence of an active tectonic line in the west side region of Suruga Bay is investigated. First, some characteristics of seismicity and mechanism of earthquakes occurring in this region are reviewed. Then, a set of faults of NW-SE direction newly found on the shore of Ookuzure-Kaigan is introduced. The fault outcrops are observed at the ends of lineaments clearly seen in an air photograph. Striations on slickensides show that they are left-lateral with slight dip slip movement. These faults are situated just on the E-F line proposed by MOGI (1977), however, slip direction is reverse to the Irozaki fault. On the same part of the west coast of Suruga Bay certain features of boundary are observed in Bouguer anomaly map and in recent crustal strain accumulation as well.
In the discussion the meaning of the tectonic line is preliminarily considered and the possibility that stress field in the Philippine sea plate differs, in this region, from that in the upper crust of Eurasian plate is proposed.
