Paleoseismology and Paleogeodesy of the Sumatran Subduction Zone

苏门答腊俯冲带的古地震学和古大地测量学

基本信息

批准号：
9804970
负责人：
Steven Ward
金额：
$ 3.58万
依托单位：
University of California-Santa Cruz
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
1998
资助国家：
美国
起止时间：
1998-08-15 至 1999-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9804970&HistoricalAwards=false
关键词：
Paleoseismology Paleogeodesy Sumatran Subduction Zone

项目摘要

9804970Ward This research is to complete analysis on coral data gathered earlier between the western coast of Sumatra and the trench of the Sumatran subduction zone, 240 km offshore. The samples consist of slabs of head corals that record sea-level changes caused by tectonic deformation related to earthquake occurrence. The nature of earthquake recurrence is poorly understood, in large part because physical models are constrained inadequately by sparse paleoseismic and paleogeodetic records and by instrumental data. This work has shown that coral "microatolls" offer an unrivalled opportunity to test models of earthquake recurrence, because they record vertical deformation through several large-earthquake cycles quite precisely in their morphology and annual banding. On the islands of the outer-arc Sumatran ridge, 120 to 130 km from the trench and about 25 km above the subduction interface, this project has shown sudden emergence of about 2 meters during the giant earthquake of 1833 and during two earlier events about AD 1608 and 1380. This implies 10 to 13 meters of slip on the subduction interface during each of these events. There is also evidence of episodic, interseismic submergence of the islands at rates that increase trenchward from about 4 to about 10 mm/yr, averaged over the past several decades and in the decades prior to each large earthquake. This grant will support the development of plausible physical models to explain the interseismic and coseismic deformation. This research is a component of the National Earthquake Hazard Reduction Program.

9804970Ward 这项研究旨在完成对早前在苏门答腊岛西海岸和离岸 240 公里的苏门答腊俯冲带海沟之间收集的珊瑚数据的分析。这些样本由头状珊瑚板组成，记录了与地震发生相关的构造变形引起的海平面变化。人们对地震复发的性质知之甚少，很大程度上是因为物理模型受到稀疏的古地震和古大地测量记录以及仪器数据的限制不充分。这项工作表明，珊瑚“微环礁”为测试地震复发模型提供了无与伦比的机会，因为它们在形态和年度带中非常精确地记录了几个大地震周期的垂直变形。在外弧苏门答腊山脊的岛屿上，距海沟 120 至 130 公里，俯冲界面上方约 25 公里，该项目显示在 1833 年的大地震和公元两次早期事件中突然出现了约 2 米的高度。 1608 和 1380。这意味着在每次事件期间俯冲界面上都有 10 到 13 米的滑移。还有证据表明，在过去几十年和每次大地震发生之前的几十年里，岛屿的间歇性地震淹没速度从每年约 4 毫米增加到约 10 毫米。这笔赠款将支持开发合理的物理模型来解释震间和同震变形。这项研究是国家地震减灾计划的一部分。