Collaborative Research: Quaternary Deformation in the Cascades Foothills and Southern Puget Lowland, Washington

9628268华盛顿州普吉特低地的蒙哥马利位于卡斯卡迪亚会聚边缘的弧前区域，胡安达-富卡板块在那里倾斜地汇聚在北美板块之下。相关的形变发生在俯冲板块边界或贝尼奥夫带上，也发生在横跨北加州、俄勒冈、华盛顿州和不列颠哥伦比亚省西南部的上(北美)板块宽广而复杂的区域。已经提出了几种解释卡斯卡迪亚边缘第四纪变形的模型，但目前的野外资料不足以对这些模型进行评价。这个项目将研究西雅图附近的一条活动断层如何继续向南滑动。这项工作是一个试点项目，目的是确定地表暴露和地震数据是否足以测试一个模型，该模型表明西雅图断层是整个普吉特-低地之下综合的区域性推覆系统的一部分。如果成功，这些结果将为理解这种跨张张构造环境提供一个亟需的模型框架，这也将为风险评估提供一个重点。

9628268 Montgomery The Puget Lowland, Washington, is in the fore-arc region of the Cascadia convergent margin, where the Juanda Fuca plate is obliquely converging beneath the North American plate. Associated deformation occurs along the subducting plate boundary or Benioff zone and also in a wide, complex region of the upper (North American) plate extending across Northern California, Oregon, Washington and Southwestern British Columbia. Several models have been proposed to explain Quaternary deformation in the Cascadia margin, but present field data is inadequate to evaluate these models. This project will examine how slip on an active fault in the vicinity of Seattle continues to the South. The work is a pilot project to determine if surface exposures and seismic data will be adequate to test a model that suggests that the Seattle fault is part of an integrated, regional thrust system under the entire Puget-Lowland. If successful, the results will provide a much needed model framework for understanding this transtensional tectonic environment, which will also provide a focus for risk assessment.