Hypocenter determination by Japan-Taiwan collaborative research to presume Philippine sea plate zone in the vicinity of Ryukyu Arc to Eastern Taiwan region.

日本与台湾合作研究确定震源，推测琉球岛弧至台湾东部地区的菲律宾海板块带。

基本信息

批准号：
14540399
负责人：
BABA Hisatoshi
金额：
$ 1.6万
依托单位：
TOKAI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

Geology and tectonics of the region between the southwestern Ryukyu arc and the eastern Taiwan are characterized by subduction or collision of the Philippine Sea plate and Eurasian plate. The present collision boundary in Taiwan is located along the Longitudinal Valley between Hualien and Taitung, but the plate boundary of the region between the northeast off Taiwan and the southwestern Ryukyu arc is not yet clear and still controversial. In order to make clear the plate boundary or configuration and tectonics in the region, it is indispensable to study the accurate seismic activities, in other words, precise hypocenter distributions, focal mechanisms, and so on.We, therefore, have been able to obtain more accurate or detailed hypocenter distributions in this region. As the results, our hypocenter locations show a large discrepancy with those of Japan Meteorological Agency and Taiwan Central Weather Bureau, which may be due to biased station networks, complex lithospheric structures and others, in this area. Recently, within a half year, four large earthquakes occurred near Yonaguni Is. (Dec.18 2001, M7.3), near Ishigaki Is. (Mar.15 2002, M6.6), and off east coast of Taiwan (Mar.31 2002, M7.2, and May.15 2002, M6.8). These earhtquake focal zones seem to align along the plate boundary, and their focal mechanisms are reflected on a complicated tectonics in the region. We describe the precise hypocentral distribution, and fault plane model of earthquake. Also we make consideration about the cause of the activity and the tectonics.

西南鲁伊基（Ryukyu）弧与台湾东部地区之间地区的地质和构造的特征是菲律宾海板和欧亚板块的俯冲或碰撞。台湾目前的碰撞边界位于Hualien和Taitung之间的纵向山谷，但是台湾东北地区和西南Ryukyu Arc之间的板块边界尚不清楚且仍然有争议。为了清除该地区的板块边界或配置和构造学，必须研究准确的地震活动，换句话说，精确的低温分布，焦点机制等是必不可少的。结果，我们的低中心位置显示出与日本气象局和台湾中央气象局的差异很大，这可能是由于该地区有偏见的车站网络，复杂的岩石圈结构等。最近，在半年内，Yonaguni附近发生了四场大地震。（2001年12月18日，M7.3），Ishigaki附近。（2002年3月15日，M6.6）和台湾东海岸（2002年3月31日，M7.2和5月15日，2002年，M6.8）。这些耳质焦距似乎沿板界对齐，它们的焦点机制反映在该地区复杂的构造上。我们描述了地震的精确下中心分布和断层平面模型。我们还考虑了活动和构造的原因。