Collaborative Research: Imaging plate boundary processes within the Cascadia subduction zone offshore central Washington with open-access marine seismic data

合作研究：利用开放获取的海洋地震数据对华盛顿中部近海卡斯卡迪亚俯冲带内的板块边界过程进行成像

• 批准号: 1333105
• 负责人: Kathleen Keranen
• 金额: $ 9万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-15 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1333105&HistoricalAwards=false
• 关键词: Collaborative; Research; Imaging; plate; boundary

Analysis of the recently-acquired multi-channel seismic (MCS) data will address a series of topics that relate to the structure of the lithosphere and the margin evolution along the central WA portion of Cascadia subduction zone, and how these relate to current seismicity patterns. Advanced processing of the MCS data is expected to identify the depth and character of the plate boundary and the amount of sediment currently being subducted will be assessed. Deformation of strata within the accretionary wedge will be mapped to track longer-term evolution of the plate interactions. Estimates of crustal hydration will be obtained from assumed seismic velocity-porosity relationships and, along interfaces, reflectivity. Maps showing the distribution of methane hydrates in the region will be produced.Results will provide a framework within which other Cascadia geoscientific studies are conducted, both for seismic processes and tectonic evolution, and are likely to have implications for hazard assessment. While this subduction zone currently has less earthquake activity than other zones around the world, onshore evidence of repeated megathrust events is clear, so it is important to understand the history of of stress buildup (strata deformation) and the extent to which fluids along faults might enable periods of 'lubricated', slow release.

对最近获得的多道地震（MCS）数据的分析将涉及一系列与岩石圈结构和沿卡斯卡迪亚俯冲带WA中部沿着边缘演化有关的主题，以及这些与当前地震活动模式的关系。预计对监控监数据的进一步处理将确定板块边界的深度和特征，并将评估目前正在俯冲的沉积物数量。将绘制增生楔内地层的变形图，以跟踪板块相互作用的长期演变。将根据假定的地震速度-孔隙度关系和沿着界面的反射率来估计地壳水合作用。将绘制显示该区域甲烷水合物分布的地图，其结果将提供一个框架，在此框架内进行其他卡斯卡迪亚地震过程和构造演化地球科学研究，并可能对灾害评估产生影响。虽然这个俯冲带目前的地震活动比世界上其他地区少，但陆上重复的巨型逆冲事件的证据是明确的，因此重要的是要了解应力积累（地层变形）的历史以及流体沿着断层的程度可能使“润滑”，缓慢释放的时期。