Toward Dynamic Models of Contemporary Plate Boundary Deformation with Application to the Taiwan Collision Zone

当代板块边界变形动态模型及其在台湾碰撞带中的应用

• 批准号: 0609620
• 负责人: Kaj Johnson
• 金额: --
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0609620&HistoricalAwards=false
• 关键词: Toward; Dynamic; Models; Contemporary; Plate

The recent catastrophic earthquakes in Sumatra and Pakistan underscore the importance of developing techniques to identify potential large seismic sources and gaining an improved understanding of plate-boundary deformation processes. Crustal deformation models constrained by geodetic, seismic, paleoseismic, and geomorphic data are the appropriate tools for probing into the physics of plate-boundary deformation. The purpose of this research is to develop dynamic models of plate-boundary deformation that incorporate GPS measurements of crustal motions with a wide variety of geologic and geophysical data sets from the Taiwan arc-continent collision zone, one of the most densely instrumented, yet poorly understood, plate boundaries. The models are dynamic in the sense that slip on faults is governed by an assumed constitutive law that relates stresses in the lithosphere to fault slip. The models being developed in this research are an extension of related kinematic models in which slip on faults is prescribed based solely on the motions of lithospheric blocks, without regard to the driving forces. The overarching questions that motivate this work are directed toward an improved understanding of factors that control the spatial and temporal distribution of lithospheric deformation in Taiwan and other plate-boundary settings: 1) How is the rapid arc-continent convergence in Taiwan distributed among the active faults and folds? 2) What role do creeping and locked fault segments play in distributing this deformation?, 3) What role does fault geometry play in distributing the deformation?, 3) Where are future earthquakes likely to occur?, and 4) How can the various disparate data sets be integrated into a comprehensive 3D model of this ongoing deformation process? In particular, the research aims to integrate the dynamic model with various data sets to obtain estimates of fault slip rates in Taiwan and determine the spatial distribution of locked sections of active faults that are likely to rupture in future earthquakes. Model predictions of fault slip rates from GPS data are constrained by paleoseismic, geologic, and geomorphic estimates of long-term slip rates. Active fault geometry and locations of creeping and locked fault patches are constrained by relocated seismicity, distributions of earthquake focal mechanisms, and locations of small repeating earthquakes. Seismic tomography constrains crustal geometry and rheology.

最近发生在苏门答腊岛和巴基斯坦的灾难性地震凸显了开发技术来识别潜在大型震源并更好地了解板块边界变形过程的重要性。受大地测量、地震、古地震和地貌数据约束的地壳变形模型是探讨板块边界变形物理的适当工具。这项研究的目的是开发板块边界变形的动态模型，该模型将地壳运动的 GPS 测量与来自台湾弧大陆碰撞带的各种地质​​和地球物理数据集相结合，该碰撞带是仪器最密集但较差的地区之一。了解，板块边界。这些模型是动态的，因为断层上的滑动受到将岩石圈中的应力与断层滑动联系起来的假设本构定律的控制。本研究中开发的模型是相关运动学模型的延伸，其中断层上的滑动仅基于岩石圈块体的运动来规定，而不考虑驱动力。推动这项工作的首要问题是为了更好地理解控制台湾岩石圈变形时空分布和其他板块边界环境的因素：1）台湾弧大陆快速辐合是如何分布在活跃板块之间的？缺陷和褶皱？ 2) 蠕动断层段和锁闭断层段在分布这种变形中起什么作用？ 3) 断层几何形状在分布变形中起什么作用？ 3) 未来地震可能发生在哪里？ 4) 各种不同的地震如何发生？数据集是否可以集成到这个持续变形过程的综合 3D 模型中？特别是，该研究旨在将动态模型与各种数据集相结合，以获得台湾断层滑移率的估计，并确定未来地震中可能破裂的活动断层锁定部分的空间分布。 根据 GPS 数据对断层滑动率进行的模型预测受到长期滑动率的古地震、地质和地貌估计的限制。活动断层的几何形状以及蠕动断层和锁定断层的位置受到重新定位的地震活动、地震震源机制的分布和小重复地震的位置的限制。地震层析成像限制了地壳几何形状和流变学。