Monitoring Sseismicity Associated With a Possible Asperity on the Cascadia Megathrust

为了研究俄勒冈州中部近海卡斯卡迪亚俯冲带沿着的异常地震活动区域，研究人员将在为期两年的短周期和宽带海底地震仪部署期间被动监测地震活动。 至少部分部署将与作为USAray实验一部分的相邻陆上部署同时进行。 在过去两年中，目标地区经历了两次中度地震和一系列小地震，现有数据表明，该地区正在俯冲的基底脊正在撞击结晶支撑物，可能造成大地测量实验在海洋板块中检测到的变形。 该项目将进一步限制这种变形。 这项研究还部分代表了对与弧前和俯冲脊的相对强度有关的假设的检验，如果这些特征中的任何一个是俯冲复合体中的强成分，则预计会有不同的地震活动模式。 更广泛的影响包括培训许多本科生和研究生，为可能在该区域最终建立的观测站建立基线数据，以及与USAray和Earthscope实验相结合。

To study a region of anomalous seismicity along the Cascadia subduction zone, offshore central Oregon, researchers will passively monitor earthquake activity during two, year-long deployments of short-period and broadband ocean bottom seismometers. At least part of the deployment will be concurrent with adjacent onshore deployments that are part of the USArray experiment. The target area has experienced two moderate earthquakes and a swarm of small earthquakes during the past 2 years, and available data suggest that a basement ridge being subducted in this area is hitting the crystalline backstop, possibly causing the deformation detected in the oceanic plate by geodetic experiments. This project will further constrain such deformation. The research also in part represents a test for hypotheses related to the relative strength of forearc and subducting ridge, with different seismicity patterns expected if either of these features is the strong component in the subduction complex. Broader impacts include training of numerous undergraduate and graduate students, establishing baseline data for a possible eventual observatory in this region, and integration with the USArray and Earthscope experiments.