Assessment of Geohazards and Geodynamics by Integrated Gravimetric and Geodetic Methods

超导重力仪的微重力监测对于地震、火山活动、地质储层注入二氧化碳运移和泄漏等地质灾害引起的地下小质量变化和重分布是有效的。然而，在地球表面获得的重力信号包括与地下变形相关的地表位移效应，因此，必须准确地估计地表变形产生的重力效应，并将其与地面测量的重力分离开来。这可以通过综合大地测量技术，如干涉合成孔径雷达（InSAR）和全球导航卫星系统（GNSS）网络来实现。为了通过综合重力和大地测量方法监测、模拟和评估地质灾害和地球动力学（图1），我建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弹簧重力仪（RG）：1)不列颠哥伦比亚省Cascadia俯冲带（CSZ）地震监测，2)育空地区Kluane湖研究站（KLRS）诱发地震活动和火山活动监测，3)AB布鲁克斯地区野外研究站（FRS）地质CO2储存监测注入羽流。iGrav SG是关键仪器，将由A-10和FG-5 AGs以及CG-5 RG提供支持。

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.