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

胡安·德·富卡板块的辐合和太平洋板块相对于北美的向西北运动导致了北美边缘向其内部几百公里处的主动变形。这种变形有可能产生巨大的破坏性地震，并且可以通过差分模式下的全球定位系统（GPS）非常精确地测量出来。调查人员将利用美国地质调查局在1991年至1995年间收集的现有GPS数据，以及美国国家大地测量局、当地测量员和PIs最近的测量结果，来检查这种变形的具体方面及其地质原因。在本研究中，PIs将重点关注俄勒冈州和华盛顿州沿海地区的北移速率及其在沿海山脉生长中的作用，沿海应变速率的变化可能与Juan de Fuca板块与北美分离的倾斜逆冲断层的分割有关，以及北移沿海地区与北美之间的边界位置。所有这些特征都在全球其他几个收敛边缘中观察到，这项针对美国太平洋西北部的重点研究将帮助我们了解其潜在原因。

9817063GoldfingerThe 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.