Configuration of Subducted Philippine Sea Plate beneath the Chubu District, Central Japan

Subduction of young plates: A case of the Philippine Sea plate beneath the Chugoku region, Japan

“…Since then, this map had served as a standard in scientific discussions on solid earth of the southwestern Japanese Islands. Yamazaki and Ooida (1985) presented a more detailed contour map for the Philippine Sea plate, but the subcrustal seismicity beneath the Chugoku region was still unknown. Miura et al (1991) studied the subcrustal seismicity in the western part of the Seto Inland Sea (Seto Naikai) and surrounding regions.…”

Seismic activity of subcrustal earthquakes and associated tectonic properties in the southeastern part of the Kinki district, southwestern Japan.

“…earthquakes with depths of 30 to 90 km are taking place. The configuration of the hypocentral distribution and the focal mechanism of these subcrustal earthquakes have been closely related to the subduction process of the Philippine Sea plate by many authors (see e.g., Kanamori and Tsumura, 1971;Shiono, 1977;Mizoue et al, 1983; Yamazaki and Ooida, 1985;Ishida and Hasemi, 1988).…”

“…Shiono (1977) found out the fact that the T axes inclined parallel to the dip of the subducted seismic zone at depths of 150-200 km in the western parts of Nankai trough (Kyushu and northern Ryukyu arc), suggesting a tectonic field of down-dip extension. Mizoue et al (1983) and Yamazaki and Ooida (1985).…”

“…Hurukawa (1981) investigated the seismic activity and the focal mechanism of the subcrustal earthquakes in the northern part of Lake Biwa and showed that this activity had some different features from those occurring along the subduction zone. Yamazaki and Ooida (1985) parceled out the subducting Philippine Sea plate lying in the Tokai district (east of the Kinki district) into three slabs according to the discontinuities between the planes of focal distribution. One of them, named "Tonankai slab" lies partly in the eastern part of the Kinki district.…”

The spatial distribution of earthquake hypocenters and the three-dimensional velocity structure in the Kanto-Tokai district, Japan.

“…Therefore, the tectonics of the Kanto-Tokai region have long been of particular interest from the viewpoint of both the earthquake prediction and tectonic studies. The spatial distribution and focal mechanisms of earthquakes in this region have been studied by many authors (TSUMURA, 1973(TSUMURA, , 1981KASAHARA, 1980;MAKI et al, 1980;YAMAZAKI and OOIDA, 1982;NAKAMURA et al, 1984;etc.). For example, TSUMURA and KARAKAMA (1981) studied those in the Kanto District, and YAMAZAKI and OOIDA (1982) studied those in the Tokai District using the data obtained from their own local networks, so that the spatial distributions of earthquake hypocenters were not homogeneous throughout the two regions.…”