Onshore-offshore broadband seismic studies of Earth structure and tectonic processes

地球结构和构造过程的陆上-海上宽带地震研究

• 批准号: RGPIN-2018-03752
• 负责人: Audet, Pascal
• 金额: $ 3.72万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712539
• 关键词: Onshore; offshore; broadband; seismic; studies

My research program focuses on two main scientific objectives: constraining the role of geological structure and processes on the dynamics of active ocean-continent plate boundaries and elucidating the growth and fate of large Cordilleras, as revealed by geophysical data. I address these objectives by developing seismic velocity models of continental and oceanic plate systems and their seismic activity using data obtained from large networks of broadband seismic instruments, both on land and offshore. In particular, I use and develop seismic analysis tools rooted in modern statistical theory to extract maximum information from these data. My research focuses on the tectonics of western Canada, which form large natural laboratories to study these scientific objectives. On the western Canadian coastline, the Pacific and Juan de Fuca oceanic plates are juxtaposed against the North American continent along two plate boundaries: the Cascadia subduction zone to the south and the Queen Charlotte-Fairweather Fault to the north. Each boundary type contains large faults that are frictionally locked for long periods of time, and slip in large (and sometimes giant) earthquakes, and therefore represent significant seismic hazard to coastal populations. The majority of these earthquakes and the faults themselves are located offshore; their study therefore requires onshore-offshore seismic data. In addition to the threat they pose to coastal areas, subduction zones leave their imprint on the continental margin by forming volcanic arcs and large back arcs that evolve into cordilleras mountain belts that are hot and easy to deform over long time scales (~Myr). The Canadian Cordillera has been active since the Mezosoic and contains important mineral and geothermal energy resources. Its current seismic activity also reflects heterogeneous stress distribution that is partly controlled by its structural and geological makeup. In this proposal I plan to use all available sources of broadband seismic data encompassing western Canada to study these large tectonic systems; importantly, my long-term vision is to work toward new broadband ocean-bottom seismograph deployments in the northeast Pacific and western Canadian Arctic and capitalize on the presence of the large USArray Transportable Array deployment and on the opportunities created by the prospective Canadian Cordillera Array initiative to study these systems and address the scientific objectives.

我的研究计划侧重于两个主要的科学目标：限制地质结构和过程对主动海洋板板边界动力学的作用，并阐明大型山脉的生长和命运，如地球物理数据所示。我通过使用从陆地和海上宽带地震仪器的大型网络获得的数据来开发大陆和海洋板系统的地震速度模型及其地震活动来解决这些目标。特别是，我使用并开发植根于现代统计理论的地震分析工具来从这些数据中提取最大信息。我的研究重点是加拿大西部的构造学，该构造形成了研究这些科学目标的大型自然实验室。在加拿大西部海岸线上，太平洋和胡安·德福卡海洋板沿两个板块边界与北美大陆并列：南部的卡斯卡迪亚俯冲带和北部的夏洛特女王的断层。每种边界类型都包含长时间摩擦锁定的大断层，并在大型（有时是巨大的）地震中滑落，因此代表了对沿海种群的严重地震危害。这些地震和断层本身都位于近海。因此，他们的研究需要陆上岸地震数据。除了对沿海地区构成威胁外，俯冲区还通过形成火山弧和大型背弧而在大陆边缘留下烙印，这些弧形变成了山脉山带，这些山脉山带炎热且易于在长时间的尺度上（〜myr）变形。自梅索斯（Mezosoic）以来，加拿大山脉（Condian Cordillera）一直活跃，并包含重要的矿物质和地热能资源。其当前的地震活性还反映了其结构和地质构成部分控制的异质应力分布。在此提案中，我计划使用所有可用的宽带地震数据来源，包括加拿大西部的西部研究这些大型构造系统；重要的是，我的长期愿景是在东北太平洋和加拿大西部北极进行新的宽带海洋底部部署，并利用大型USARRAY可运输阵列部署以及前瞻性加拿大Cordillera Array Initiative创造的机会研究这些系统并解决科学目标。