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

威廉姆斯0106798俯冲带的地表变形通常被解释为俯冲板块和上覆板块之间的逆冲边界上的运动。 弹性半空间位错（EHSD）模型经常被用来推断从地面大地测量观测和地震危险性的断层的部分被完全或部分锁定方面的断层上的滑动分布进行评估。 这些模型是有吸引力的，因为它们的简单，但假设所有的表面变形是由于运动的断层嵌入在一个均匀的弹性半空间导致一些不切实际的行为。 而不是考虑整个系统，这个项目将只考虑部分的覆盖板的行为弹性在一段时间内的利益。地表变形是由于沿着逆冲断层边界和沿着有限弹性区域（上覆板块）底部施加的应力变化或速率造成的。 这种方法提供了一个更有前途的手段，了解俯冲带的物理，使更少的隐含假设比EHSD模型。 将该方法的反演结果与EHSD模型的反演结果进行了比较。 调查人员将首先考察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。 其他研究地区将包括日本、苏门答腊、喜马拉雅山和新西兰。 这项研究的结果应该有重要的意义，在断层摩擦研究和地震灾害的研究，并在了解板块驱动力和阻力。

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.