南海トラフから沈み込むフイリピン海プレートのP波速度構造と西南・中部日本の地震活動および火山活動

概要

論文の詳細を見る
We derive a three-dimensional P-wave velocity structure beneath the Japanese Islands through a tomographic inversion of travel time data of the Seismological Bulletin of the Japan Meteorological Agency (JMA) during the period from October 1994 to September 1997. We use 53,230 arrival time data from 1,180 earthquakes observed at 220 JMA stations to obtain velocity anomalies, corrections to source parameters, and station corrections. We find high-velocity anomalies indicating the Philippine Sea plate subducting from the Nankai trough in the Shikoku, Chugoku, Kinki and Chubu regions, and low-velocity anomalies of the oceanic crust at the top of the subducting Philippine Sea plate beneath the Kii peninsula. The Philippine Sea plate subducting from the Nankai trough has reached the upper mantle beneath the coast of the Japan Sea and the region where Quaternary volcanoes are observed, although few subcrustal earthquakes occur near the leading edge of the subducting Philippine Sea plate. Low-velocity anomalies are found beneath these volcanoes, and the low-velocity anomalies are underlaid by the high-velocity anomalies of the Philippine Sea plate. We can suggest that these volcanoes are rooted in the magma generated by the subduction of the Philippine Sea plate. The Philippine Sea plate subducting from the Nankai trough may be divided into at least four segments: the Nankaido region, the western and eastern parts of the Kii peninsula, and the Tokaido region, and this segmentation may have a significant influence on the recurrence of great earthquakes along the Nankai trough.

南海トラフから沈み込むフイリピン海プレートのP波速度構造と西南・中部日本の地震活動および火山活動

スポンサーリンク

概要

著者

関連論文

スポンサーリンク