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.

Williams 0106798俯冲区域处的表面变形通常用俯冲板和覆盖板之间的推力边界上的运动边界来解释。 弹性半空间脱位（EHSD）模型经常用于从表面测量观测的断层上推断出滑动分布，并通过完全或部分锁定断层的哪些部分来评估地震危险。 这些模型由于其简单性而具有吸引力，但是假设所有表面变形都是由于嵌入均匀的弹性半空间中的断层运动引起的，这会导致一些不切实际的行为。 该项目不再考虑整个系统，而是仅考虑在感兴趣的时期弹性行为的层面板的部分。表面变形是由于沿推力断层边界和有限弹性区域（覆盖板）的底部施加的应力变化或速率而发生的。 这种方法提供了一种比EHSD模型更有前途的理解俯冲区域物理学的方法，并做出的隐性假设更少。 使用此方法的反转结果将被比较并与使用EHSD模型的反演结果。 研究人员最初将检查俄勒冈州和华盛顿的卡斯卡迪亚俯冲带，以及阿拉斯加的基奈半岛。 其他研究领域将包括日本，苏门答腊，喜马拉雅山和新西兰。 这项研究的结果应对断层摩擦研究和地震危害研究以及理解板驾驶和电阻力有重要意义。