DESCRIPTION OF SUBMARINE ACTIVE FAULTS AROUND JAPANESE ISLANDS-A BASIC INVESTIGATION FOR SUBMERSIBLE SEISMOGEOLOGY-

Seismotectonics along the eastern Nankai Trough werere-investigated on the basis of photographic analyzes of still-photos and video films recorded during the KAIKO and KAIKO-NANKAI programs, using structural indicators such as slip sense of fault, clastic dikes and joints. Tectonic stress orientation differs among the inner and outer tough slopes, indirectly indicating eastern motion of the Amurian plate (Enshu-nada deepsea terrace) and northward motion of the Philippine Sea plate (Zenisu Ridge). On the contrary, no such kind of stress zonation is found along the eastern maegin of Japan Sea, possibly because the plate boundary between the Amur and the Okhotsk plates are too immature.