COLLABORATIVE RESEARCH: Forearc Deformation at Subduction Zone Cusp and Plate Coupling Variations in Cascadia

9814926麦卡弗里胡安·德富卡板块的会聚和太平洋板块相对于北美的西北运动导致北美边缘向内部数百公里处发生活跃变形。 这种变形有可能产生大的破坏性地震，并且可以用以差分模式工作的全球定位系统（GPS）非常准确地测量。 调查人员将利用美国地质调查局在1991年至1995年沿着收集的现有GPS数据，以及国家大地测量局、当地测量员和PI最近进行的测量，以检查这种变形的具体方面及其地质原因。 在这项研究中，PI将集中在俄勒冈州和华盛顿的沿海地区向北运输的速度和作用，这种运输在沿海山脉的增长，应变率的变化沿着海岸可能与分割的倾斜逆冲断层胡安德富卡板块从北美，和向北移动的沿海地区和北美之间的边界的位置。 所有这些特征都在全球其他几个收敛边缘中观察到，这项在美国太平洋西北部的重点研究将帮助我们了解其根本原因。

9814926McCaffrey The convergence of the Juan de Fuca plate and the northwestward motion of the Pacific plate relative to North America result in active deformation of the North American margin several hundred kilometers into its interior. This deformation has the potential of producing large, damaging earthquakes and can be measured very accurately with the Global Positioning System (GPS) operating in the differential mode. The investigators will utilize pre-existing GPS data gathered by the US Geological Survey between 1991 and 1995 along with more recent measurements made by the National Geodetic Survey, local surveyors, and by the PIs to examine specific aspects of this deformation and their geological causes. In this study the PIs will focus on the rate of northward transport of the coastal regions of Oregon and Washington and the role this transport plays in the growth of coastal mountains, the variations in strain rates along the coast possibly related to segmentation of the dipping thrust fault separating the Juan de Fuca plate from North America, and the location of the boundary between the northward moving coastal region and North America. All of these features are observed in several other convergent margins globally and this focused study in the US Pacific Northwest will help us understand their underlying causes.