MONITORING CRUSTAL DEFORMATION AND GRAVITY CHANGE CAUSED BY THE TERRESTRIAL WATER LOAD IN THE THREE GORGES AREA BASE ON CORS NETWORK

The Three Gorges region is rich in water resources. With the added impact of impoundment and discharge of the Three Gorges Reservoir, the regional hydrodynamic environment is complex, and research on the impacts of this terrestrial water is still relatively scarce. Using the CORS network supplemented by a small amount of gravity station data, and using the load deformation and gravitational field spherical harmonic analysis method, the crustal deformation and gravity changes caused by the terrestrial water in the Three Gorges area are studied. We find that it is possible to use the CORS network to monitor the crustal deformation and ground-level gravity changes that are caused by the terrestrial water load. The impact of the terrestrial water load is up to the centimeter-level on the vertical deformation, less on the horizontal deformation, and up to hundreds of microgals in the ground level gravity variations. From January 2011 to June 2015, the vertical deformation caused by the terrestrial water load change tends to be balanced, and the influences of gravity changes are mainly concentrated in the Three Gorges Reservoir and the Jianghan Plain. Except for some areas, the crustal vertical deformations caused by the terrestrial water measured by CORS and GRACE are highly consistent in their distribution patterns and trends. In this paper, the research results can be used for monitoring the hydrodynamic environment and for the protection and utilization of water resources, which can also be used to dynamically maintain the elevation and gravity benchmarks.