Collaborative Research: Resolving Structural Control of Episodic Tremor and Slip Along the Length of Cascadia

地球望远镜公司灵活阵列的宽带和短周期地震仪器的部署正在用于研究沿卡斯卡迪亚俯冲带长度的分段。该实验旨在研究幕式震动和滑动与覆盖板块的三维结构之间的潜在联系，包括地质地体的差异和与地震孕育行为有关的特征。灵活的阵列部署是对移动阵列和永久网络的现有地震台站的补充，以提供统一密集的网络，典型的台站间距为40公里。空间站的覆盖范围从加利福尼亚州北部，穿过俄勒冈州，延伸到华盛顿的北部边界，从海岸到火山弧的东侧。这一密集的地震台覆盖范围与板块边界观测站增强的全球定位系统仪器相结合，正被用于研究整个卡斯卡迪亚俯冲带内非火山地震和慢滑事件的空间和时间模式。初步工作揭示了幕式震颤和滑动特征的分段，这似乎与俯冲板块无关。对上覆大陆板块的地震成像将提供必要的构造控制，以调查与上板块地质和流变学沿走向变化的潜在关系。

A deployment of broadband and short period seismic instruments from Earthscope's Flexible Array is being used to study segmentation along the length of the Cascadia subduction zone. The experiment is designed to examine the potential links between episodic tremor and slip and the three-dimensional structure of the overriding plate including differences in the geologic terranes and features associated with seismogenic behavior. The Flexible Array deployment complements existing seismic stations from the Transportable Array and permanent networks to provide a uniformly dense network with a typical station spacing of 40 km. Station coverage extends from northern California, through Oregon, to the northern border of Washington, from the coast to the eastern side of the volcanic arc. This dense seismic station coverage, combined with enhanced GPS instrumentation from the Plate Boundary Observatory, is being used to investigate spatial and temporal patterns of non-volcanic tremor and slow slip episodes throughout the entire Cascadia subduction zone. Preliminary work reveals segmentation in the characteristics of episodic tremor and slip which do not appear to correlate with the subducting plate. Seismic imaging of the overriding continental plate will provide the necessary structural control to investigate potential relationships with along-strike variations in geology and rheology of the upper plate.