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: $ 7.43万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751204
• 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科学目标：限制地质结构和过程对活跃海洋-大陆板块边界动力学的作用，以及阐明地球物理数据揭示的大型科迪勒拉山脉的生长和命运。我通过使用从陆地和海上宽带地震仪器大型网络获得的数据开发大陆和海洋板块系统及其地震活动的地震速度模型来实现这些目标。特别是，我使用和开发植根于现代统计理论的地震分析工具，从这些数据中提取最大的信息。我的研究重点是加拿大西部的构造，这些构造形成了大型自然实验室来研究这些科学目标。在加拿大西部海岸线上，太平洋板块和胡安德富卡板块沿着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皇后-费尔韦瑟断层。每种边界类型都包含长时间摩擦锁定的大型断层，并在大（有时是特大）地震中滑动，因此对沿海人口构成重大地震危害。大多数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和海上地震数据。除了对沿海地区构成威胁之外，俯冲带还通过形成火山弧和大型后弧在大陆边缘留下了印记，这些火山弧和大型后弧演变成高温且容易在长时间尺度上变形的山脉带（〜Myr）。加拿大科迪勒拉山脉自中生代以来一直活跃，蕴藏着重要的矿产和地热能源。其当前的地震活动也反映了不均匀的应力分布，该分布部分受其结构和地质组成的控制。在本提案中，我计划使用涵盖加拿大西部的所有可用宽带地震数据源来研究这些大型构造系统；重要的是，我的长期愿景是致力于在东北太平洋和加拿大西部北极地区部署新的宽带海底地震仪，并利用大型 USArray 可移动阵列部署的存在以及加拿大科迪勒拉阵列计划所创造的机会研究这些系统并实现科学目标。