Illuminating northern Cascadia earthquake faulting using satellite and airborne geodesy

利用卫星和机载大地测量学阐明卡斯卡迪亚北部地震断层

• 批准号: RGPIN-2017-04029
• 负责人: NISSEN, EDWIN
• 金额: $ 2.33万
• 依托单位: University of Victoria
• 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=750982
• 关键词: Illuminating; northern; Cascadia; earthquake; faulting

Earthquake faulting helps shape our planet, controls the distribution of key natural resources, and impacts our climate. Earthquakes are also amongst the most significant global natural hazards, with millions of fatalities forecast this century and large parts of Canada at risk from damaging shaking and tsunami. Understanding what governs the location, size, and timing of earthquakes is therefore one of the grand challenges of geophysics. In moving to the University of Victoria in January 2017, I seek to tackle this challenge by building a new research group focused primarily on the tectonics of northern Cascadia. This Discovery Grant - together with a Canadian Foundation for Innovation proposal which supports related infrastructural needs - will fund two distinct projects, outlined below. Both elements exploit a new wave of satellite and airborne sensors which are revolutionizing our ability to map surface deformation and topography associated with earthquake faulting. Further motivation is provided by a recent global surge of megathrust earthquakes which have torn up the rule book on subduction zone behaviour.Part A: Mapping Cascadia surface deformation with InSARWe will use a new wave of Interferometric Synthetic Aperture Radar (InSAR) satellites to produce the first spatially-continuous surface deformation measurements that span the entire Cascadia fore-arc. InSAR can provide vastly-improved spatial coverage and enhanced sensitivity to vertical displacements compared to the sparse Global Positioning System (GPS) stations currently used for deformation monitoring. A key objective is to map patterns of locking and stable slipping of the megathrust, in order to constrain the likely down-dip limit of (future) seismic slip and identify any variations along the strike of the subduction zone. A secondary goal is to detect upper plate deformation associated with shallow crustal faults, magmatism, and landsliding.Part B: Mapping upper plate faulting with airborne lidarGPS measurements imply permanent shortening landward of the subduction zone, but the responsible upper plate faults are largely unknown. Signatures of past shallow earthquakes are contained within the topography, but are inaccessible to traditional photographic remote sensing due to dense vegetation. By leveraging existing lidar holdings and collecting our own new data from an unmanned aerial vehicle platform, we will peer beneath the forested cover for the first time. Our aims are to map upper plate faults, determine their sense and rate of slip through ensuing paleoseismic work, and establish their role in fore-arc deformation kinematics.By collaborating with NRCan scientists at the nearby Pacific Geoscience Centre on both projects, we will ensure that results are translated into tangible societal benefits such as improvements to seismic monitoring capabilities and probabilistic seismic hazard assessments.

地震断层有助于塑造我们的星球，控制关键自然资源的分布并影响我们的气候。地震也是全球最重要的自然危害之一，本世纪的数百万次死亡预测，加拿大大部分地区面临损害摇动和海啸的风险。因此，了解地震的位置，规模和时机是什么是地球物理学的巨大挑战之一。在2017年1月搬到维多利亚大学时，我试图通过建立一个主要关注北卡斯卡迪亚构造的新研究小组来应对这一挑战。这项发现赠款 - 以及支持相关基础设施需求的加拿大创新提案基金会将资助下面概述的两个不同的项目。这两个元素都利用了一波新的卫星和空中传感器，这些传感器正在彻底改变我们绘制与地震断层相关的表面变形和地形的能力。最近的全球巨型地震激增提供了进一步的动机，该地震已经撕毁了俯冲带行为的规则簿。部分：与Insarwe一起绘制Cascadia表面变形将使用新的干涉合成孔径雷达（Insar）卫星来产生该卫星第一个跨越整个Cascadia fore-arc的空间连续表面变形测量。与当前用于变形监测的稀疏全局定位系统（GPS）站相比，Insar可以提供大量的空间覆盖范围和对垂直位移的敏感性增强。一个关键的目的是绘制锁定和稳定滑动的模式，以限制（未来）地震滑移的可能下倾限，并确定俯冲带罢工沿撞击区的任何变化。次要目标是检测与浅层地壳断层，岩浆和滑道相关的上板变形。部分B：用空气寄宿利达尔格普斯测量值映射上板故障，这意味着俯冲带的永久缩短陆地，但负责任的上板故障在很大程度上是未知的。过去浅地震的签名包含在地形中，但由于茂密的植被引起的传统照相遥感无法访问。通过利用现有的LiDar Holdings并从无人驾驶飞机平台收集我们自己的新数据，我们将首次凝视着森林的封面。我们的目的是绘制上板故障，通过随之而来的旧作品来确定其意义和滑倒速度，并确定它们在前弧变形运动学中的作用。通过与附近太平洋地球科学中心的NRCAN科学家在这两个项目上合作，我们将确保确保该结果转化为有形的社会益处，例如改善地震监测能力和概率地震危险评估。