Assessment of Geohazards and Geodynamics by Integrated Gravimetric and Geodetic Methods

利用超导重力仪进行微重力监测，可以有效地估计地震、火山活动等地质灾害引起的微小地下质量变化和再分布，以及注入的二氧化碳向地质储层的迁移和泄漏。然而，在地球表面获取的重力信号包括与地下变形有关的地表位移的影响，因此，必须准确地估计地表变形的重力效应，并将其与地表测量的重力分离。由于综合大地测量技术，如干涉合成孔径雷达和全球导航卫星系统网络，这成为可能。为了用重力和大地测量综合方法监测、模拟和评估地球灾害和地球动力学(图1)，我提议在加拿大西部和西北部的三个地点部署IGRAV超导(SG)、A-10绝对(AG)和CG-5春季重力仪(RG)：1)不列颠哥伦比亚省的卡斯卡迪亚俯冲带(CSZ)用于地震监测；2)育空的Kluane湖研究站(KLRS)用于诱发地震和火山活动；3)野外研究站(FRS)位于阿肯色州布鲁克斯的地质CO2储藏室用于注入烟羽的监测。IGrav SG是A-10和FG-5 AGG和CG-5 RG将支持的关键仪器。 时变的2D和3D重力监测和地下建模将由一体化的SG-AG-RG进行。地表位移将通过InSAR测量和全球导航卫星系统网络数据进行估计和建模。还将进行重力和地面变形的联合反演模拟，以得出地下质量再分布模型。这些新的方法已经由申请人开发，并在期刊出版物和专利中证明是有效的。重力仪将在大学实验室进行校准，并根据现场的数据质量和重力信号中记录的危险事件依次部署在三个地点进行数据采集。 这是一项全面的重力和大地测量研究，旨在更好地了解地震地质灾害和确保碳储存。它还集成了最先进的卫星雷达、遥感和大地测量技术，这些技术可以很容易地应用于加拿大其他地方和世界各地。这项研究将通过一个更现实的地球动力学模型，为了解构造活动的接近真实的行为提供新的见解。未来的地质灾害将造成人员伤亡和财产损失。如果能够检测到地震前兆，就可以用于公共安全和政策制定。预计这项研究的结果将提供有关二氧化碳储藏中密度和质量平衡变化、流体流动和渗透率测量以及压力变化的新信息，这些信息随后将与地震监测等其他技术的结果相结合，以更好地解释二氧化碳储存变化。

Micro gravimetric monitoring with superconducting gravity meter is effective for estimating small subsurface mass change and redistribution caused by geohazards such as earthquakes, volcanism, and migration and leakage of injected CO2 into geological reservoirs. The gravity signals acquired at the Earth's surface, however, include the effects of surface displacement related to subsurface deformation, and hence, the gravity effect from surface deformation must be accurately estimated and separated from the measured gravity at the surface. This became possible by integrated geodetic techniques such as Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS) network. In order to monitor, model, and assess geohazards and geodynamics by integrated gravimetric and geodetic methods (Fig. 1), I propose to deploy iGrav superconducting (SG), A-10 absolute (AG), and CG-5 spring gravimeters (RG) to three sites in western and northwestern Canada: 1) the Cascadia subduction zone (CSZ) in BC for earthquake monitoring, 2) the Kluane Lake Research Station (KLRS) in Yukon for induced seismicity and volcanic activity, and 3) the Field Research Station (FRS) geological CO2 storage in Brooks, AB for injected plume monitoring. iGrav SG is the key instrument which will be supported by A-10 and FG-5 AGs and CG-5 RG. Time-varying 2D and 3D gravity monitoring and subsurface modelling will be conducted by integrated SG-AG-RG. Surface displacement will be estimated and modelled by InSAR measurements and GNSS network data. A joint inversion modelling of gravity and ground deformation will be also conducted to derive a subsurface mass redistribution model. These novel methodologies have been developed by the applicant and proven effective in journal publications and patents. Gravity meters will be calibrated at the university Lab and deployed at three sites in turn for data acquisition, depending on the site's data quality and hazard events recorded in the gravity signals. This is a comprehensive gravimetric and geodetic research for a better understanding of the seismic geohazards and securing carbon storage. It also integrates the most advanced satellite radar remote sensing and geodetic technologies that can be readily applied elsewhere in Canada and around the world. This research will provide novel insight into the near-true behavior of tectonic activity through a more realistic geodynamic model. Future geohazards will cost human lives and cause property damage. If the detection of precursors of an earthquake is possible, it can be used for public safety and policy making. It is anticipated that the results from this study will provide new information about the density and mass balance variations, fluid flow and permeability measures, and pressure changes in the CO2 reservoirs, which will subsequently be integrated with the findings of other techniques, such as seismic monitoring, for better interpretation of CO2 storage changes.