日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 S (固体地球科学) » S-CG 固体地球科学複合領域・一般

[S-CG57] 日本列島の構造と進化: 島弧の形成から巨大地震サイクルまで

2019年5月29日(水) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:佐藤 比呂志(東京大学地震研究所地震予知研究センター)、篠原 雅尚(東京大学地震研究所)、石川 正弘(横浜国立大学大学院環境情報研究院)、松原 誠(防災科学技術研究所)

[SCG57-P05] 南海トラフ周辺海域の三次元速度構造

*勝山 美奈子1仲西 理子1新井 麗1田中 恵介1高橋 成実2鎌田 弘己1金田 義行3 (1.国立研究開発法人海洋研究開発機構、2.国立研究開発法人防災科学技術研究所、3.香川大学)

キーワード:3次元速度構造、南海トラフ、沈み込み帯

This is a part of the project “Comprehensive evaluation of faults information on offshore Japan”, by the Ministry of Education, Culture, Sports, Science and Technology (MEXT). The project consists of three themes, 1) Collecting seismic survey data and building a database of offshore faults, 2) Interpreting distribution of active faults using seismic data collected, and conducting the seismic re-processing by leading-edge seismic technology for the seismic data obtained in previous decades, 3) Building the fault models for a simulation of strong motion and tsunami disaster, based on the interpreted faults. Our purpose of this study is make a 3D velocity model in the Nankai Trough to provide with the support we needs to interpret faults.
The Nankai Trough, where the Philippine sea plate is subducting beneath the Eurasian plate. Some seamounts and ridges are subducted here.
3D velocity model was constructed by seismic data and ocean bottom seismometer(OBS) refraction survey data which were obtained by a various agencies and private companies. Horizons such as acoustic basment and unconformity were interpreted using reflection seismic sections. Conrad discontinuity and Mohorovicic discontinuity were interpreted on refraction surveys and consulted previous study. Layer structure and velocity model were created on these horizons.
We obtain a result that understands geological structure in Nankai Trough. So in this session, we will take a discussion concerning structural characteristic based on the 3D velocity model.