Subduction zone seismic hazards, oceanic crust evolution and paleoclimate reconstruction

这项拟议的工作将调查影响我们社会的自然现象。该提案的重点是研究俯冲和实验室内地震，以及与之相关的地震危害。俯冲地震和板内地震都是俯冲带所特有的，俯冲带是洋板俯冲或俯冲到大陆板块之下的区域。板块间界面上产生的俯冲地震是地球上最大的地震(震级&gt；8-9)。台内地震是在俯冲的大洋板块内产生的，震级可达7-8级。俯冲带地震对沿海社区构成巨大威胁，2004年苏门答腊岛9.3级大地震和随后导致数十万人死亡的海啸悲惨地说明了这一点。该项目将测试在广角折射工作、热模拟结果和地震活动数据的支持下，地震反射成像是否可以用于俯冲地震破裂区的高分辨率制图。同样的方法将用于确定穿透深度和俯冲板块中储存的水的体积之间的关系，以及观测到的实验室内地震活动的频率和最大震级之间的关系。预期结果(例如，俯冲地震破裂的陆地范围和卡斯卡迪亚边缘的实验室内地震的最大震级)应为改进概率地震危险图提供必要的限制。这样的项目对加拿大和加拿大人来说很重要，因为卡斯卡迪亚北部俯冲带位于加拿大西部近海。拟议的研究还将侧重于使用探地雷达来成像沙丘的内部几何图形，并研究它们如何随时间演变。沙丘对气候变化高度敏感，代表着过去气候条件的宝贵档案。将结合遥感、地质年代测定和地貌制图结果对探地雷达图像进行分析，目的是重建导致所调查沙丘形成的第四纪晚期局部古气候。最近的气候变化引起了公众的极大关注。

The proposed work will investigate natural phenomena that impact our society. The thrust of the proposal is focused on studying subduction and intraslab earthquakes, and the seismic hazards associated with them. Both subduction and intraslab earthquakes are unique to subduction zones, regions of underthrusting where the oceanic plates dip or subduct underneath the continental plates. Subduction earthquakes, generated on the interplate interface, are the largest earthquakes on Earth (magnitudes >8-9). Intraslab earthquakes are generated within subducting oceanic plate and have magnitudes that can be >7-8. Subduction zone earthquakes pose a huge threat to coastal communities as was tragically illustrated in 2004 by the giant magnitude 9.3 Sumatra earthquake and the subsequent tsunami that killed hundreds of thousands of people. This project will test if seismic reflection imaging, supported by wide-angle refraction work, thermal modeling results and seismicity data, can be used for high-resolution mapping of subduction earthquake rupture areas. The same methodology will be used to determine the relationship between the depth of penetration and volume of water stored in the subducting plates, and the observed frequency and maximum magnitude of intraslab seismicity. The anticipated results (e.g., landward limit of subduction earthquake rupture and maximum magnitude of intraslab earthquakes at the Cascadia margin) should provide constraints needed for improved probabilistic seismic hazards maps. Projects like this are important to Canada and Canadians because the northern Cascadia subduction zone is located offshore western Canada. The proposed research will also focus on using ground penetrating radar to image the internal geometry of sand dunes and to study how they evolve through time. Sand dunes are highly sensitive to climate variability and represent valuable archives of past climatic conditions. Ground penetrating radar images will be analyzed together with remote sensing, geochronological dating, and geomorphic mapping results with the goal to reconstruct the Late Quaternary local paleoclimate responsible for the formation of the investigated sand dunes. Recent climate change is of great public interest.