Collaborative Research: Paleoseismology and Paleogeodesy of the Sumatran Subduction Zone

9903443爱德华以前的工作已经证明，珊瑚“微环礁”提供了一个无与伦比的机会来测试地震复发的模型，因为它们在形态和年度带状上非常准确地记录了几次大地震循环中的垂直形变。在苏门答腊岛西海岸和苏门答腊岛俯冲带海沟之间，收集到的几块头珊瑚记录了海平面的变化，引起了垂直的震间和同震变形。在外弧脊的岛屿上，研究人员记录了1833年大地震期间突然出现的1-2米的高度，而在公元1608年和1380年左右的两次较早的地震中，珊瑚抬升的幅度类似，这表明这样的事件可能每隔230年再次发生一次。在这些大型涌现事件之间，珊瑚头在海沟130公里范围内快速潜没，在海沟130-200公里范围内快速涌出，在距海沟约240公里的大陆海岸记录到近稳定，这种模式可能与震间应变累积模型相一致。这项提议将继续对苏门答腊岛俯冲带进行调查，利用珊瑚地层学、地貌学和地质年代学研究1833年的大地震及其前身。

9903443 EdwardsPrevious work has demonstrated 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. Between the western coast of Sumatra and the trench of the Sumatran subduction zone, several collected slabs of head corals record sea-level changes caused vertical interseismic and coseismic deformation. On the islands of the outer-arc ridge, work has documented sudden emergence of 1-2 meters during the giant earthquake of 1833, and corals uplifted similar amounts during two earlier events about AD 1608 and 1380 suggest such events might recur about every 230 years. In periods between these large emergence events, coral heads record rapid submergence within 130 km of the trench, rapid emergence between 130 and 200 km of the trench, and near-stability on the mainland coast, about 240 km from the trench, and this pattern may be consistent with interseismic strain accumulation models. This proposal will continue the investigation of the Sumatran subduction zone, studying the giant 1833 event and its predecessors using coral stratigraphy, morphology, and geochronology.