Investigation of Surface Deformation at Subduction Zones using a Finite Plate Model

使用有限板模型研究俯冲带的表面变形

• 批准号: 0106798
• 负责人: Charles Williams
• 金额: $ 10.46万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-15 至 2003-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0106798&HistoricalAwards=false
• 关键词: Investigation; Surface; Deformation; Subduction; Zones

Williams 0106798 Surface deformation at subduction zones is generally interpreted in terms of movement on the thrust boundary between the subducting slab and the overriding plate. Elastic half-space dislocation (EHSD) models are frequently used to infer a slip distribution on the fault from surface geodetic observations and seismic hazard is evaluated in terms of which portions of the fault are fully or partially locked. These models are appealing because of their simplicity, but the assumption that all surface deformation is due to movement on a fault embedded in a homogeneous elastic half-space leads to some unrealistic behavior. Rather than considering the entire system, this project will consider only the portion of the overriding plate that behaves elastically over the time period of interest. Surface deformation occurs as a result of stress changes or rates applied along the thrust fault boundary and along the base of a finite elastic region (the overriding plate). This approach offers a more promising means of understanding the physics of subduction zones and makes fewer implicit assumptions than do EHSD models. Inversion results using this method will be compared and contrasted with those using EHSD models. The investigators will initially examine the Cascadia subduction zone in Oregon and Washington, and the Kenai Peninsula in Alaska. Additional study areas will include Japan, Sumatra, the Himalayas, and New Zealand. The results of this study should have important implications in fault friction studies and earthquake hazard research, and in understanding plate driving and resistive forces.

威廉姆斯0106798俯冲带的地表变形一般用俯冲板和逆冲板块之间的逆冲边界上的运动来解释。弹性半空间位错(EHSD)模型经常被用来从地表大地测量数据中推断断层上的滑动分布，并根据断层的哪一部分被完全或部分锁定来评估地震危险性。这些模型很吸引人，因为它们简单，但假设所有的地表变形都是由于嵌入在均匀弹性半空间中的断层上的运动导致的，导致了一些不切实际的行为。而不是考虑整个系统，这个项目将只考虑在感兴趣的时间段内弹性行为的覆盖板块部分。地表变形是沿逆冲断层边界和沿有限弹性区域(覆盖板块)底部施加的应力变化或速率的结果。与EHSD模型相比，这种方法提供了一种更有希望的方法来理解俯冲带的物理特性，并做出了更少的隐含假设。将该方法的反演结果与EHSD模型的反演结果进行了对比。调查人员将首先检查俄勒冈州和华盛顿州的卡斯卡迪亚俯冲区，以及阿拉斯加的基奈半岛。其他研究地区将包括日本、苏门答腊岛、喜马拉雅山脉和新西兰。这项研究的结果将对断层摩擦研究和地震危险性研究以及了解板块驱动力和阻力具有重要意义。