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.

9804970这项研究是为了完成苏门答腊西部海岸和苏门答腊俯冲带240公里的苏门答腊俯冲带之间收集的珊瑚数据的分析。样品由头部珊瑚的平板组成，这些平板记录了与地震发生有关的构造变形引起的海平面变化。地震复发的性质知之甚少，这在很大程度上是因为物理模型被稀疏的古糖酶和古地球遗传记录以及工具性数据所束缚不足。这项工作表明，珊瑚的“微蓄能”为测试地震复发的模型提供了无与伦比的机会，因为它们通过几个大地质周期记录了垂直变形，这在其形态和年度频段中非常精确。在距离沟渠120至130公里的外部Arc Sumatran Ridge岛上，在俯冲界面上方约25公里，该项目在1833年的巨型地震中突然出现了约2米的突然出现，并且在两个早期的AD 1608和1380的较早事件中，这一事件突然出现。这暗示了每种事件的10至13米。也有证据表明，岛屿上有偶发性的，经过震撼的淹没，在过去的几十年中，在每次大地震之前的几十年中，在大约4毫米/年将风trench的平均值增加到约10毫米/年。该赠款将支持合理的物理模型的发展，以解释经济震荡和coseis震动变形。这项研究是国家地震危害计划的组成部分。