地震分布から求めた南西諸島における沈み込んだフィリピン海プレートの形状

概要

論文の詳細を見る
We calculated the contour of depth-distribution of hypocenters in the Nansei islands, southwest of Japan. The contours correspond to the subducted Philippine Sea plate. The contours were computed using the EHB hypocenters catalogue, whose hypocenter parameters were calculated using the global velocity heterogeneity and the depth-phases. The resulting showed the northeastward dipping Philippine Sea plate. which is steeper than the plate models computed using other hypocenters catalogues. This suggests that the depths of hypocenters by the EHB catalogue are deeper than those by other catalogues in the Nansei islands. Axes of the Okinawa Trough are located at the depth of 100 to 150 km in the central and southern Nansei islands. However, those are located at the depth of 150 km and there is no plate under the axes in the west of Kyushu.