Collaborative Research: Paleoseismology and Paleogeodesy of the Sumatran Subduction Zone

本研究继续对苏门答腊俯冲带的古地震学和古大地测量学进行研究，以确定断层破裂之间可能的周期规律、断层滑动模式的可重复性、地质结构对断层破裂的影响以及地震/地震耦合随时间的变化。这项研究的核心是使用珊瑚头（Porites和其他属），它们对海平面的变化非常敏感，误差只有几厘米。年生长带给出了相对误差为几年的时间序列，而U-Th定年法给出了误差为十年的日期。与地震相关的垂直形变（古地震学）和地震间隔的形变（古大地测量学）的震级是由这些数据确定的。正在对结果进行模拟，并利用历史地震（来自各种来源的地震图）来确定分段边界是否影响历史破裂的尺寸。该项目的具体目标是：(1)更好地表征1681、1797和1833事件的源参数；(2)确定这些事件的南部边界；(3)追溯至14世纪；(4)确定1861年和1907年地震的震源特征；(5)苏门答腊断层大地震模型历史地震记录；(6) 1861年、1797年和1833年3个地区的地震应变特征。

EAR-0207690University of California-Santa CruzThis study continues investigations of the paleoseismology and paleogeodesy of the Sumatran subduction zone in order to determine possible regularity of periods between fault ruptures, repeatability of pattern of slip on faults, influence of geologic structure on fault rupture, and variation of seismic/aseismic coupling with time. The centerpiece of the study is the use of coral heads (Porites and other genera) that are sensitive to sea level changes with uncertainties of a few centimeters. Annual growth bands give time-series with relative errors of a few years and U-Th dating of the heads gives dates with errors of a decade. The magnitude of vertical deformation associated with earthquakes (paleoseismology) and deformation in intervals between earthquakes (paleogeodesy) are being determined from these data. Results are being modeled and historical earthquakes (seismograms from a variety of sources) are being used to determine if segment boundaries influenced dimensions of historical ruptures. The specific goals of this project are to: (1) better characterize source parameters of 1681, 1797, and 1833 events; (2) determine southern limit of these events; (3) extend record back to 14th century; (4) determine source characteristics of 1861 and 1907 quakes; (5) model historical seismograms of large quakes on Sumatran fault; (6) characterize aseismic strain events in 1861, 1797, and 1833 regions.