Study on the spatial distribution pattern of correlation between surface deformation and reservoir water level in the Three Gorges Reservoir area

Abstract

The deformation characteristics of landslides in the Three Gorges Reservoir area have been proven to be closely related to periodic reservoir water level fluctuations and seasonal rainfall. However, most past studies have focused on the deformation characteristics of a single landslide that occurred on the reservoir bank and the influence pattern of reservoir water level. The spatial influence characteristics of reservoir water level need further analysis. To do so, we used multi-temporal InSAR monitoring technology with the Sentinel-1A images acquired between 2017 and 2019 to generate hillslope deformation time series data at the front edge of the Three Gorges Reservoir area. By conducting Pearson correlation coefficient analysis on the deformation and reservoir water level, it was found that in space, the slope units closer to the reservoir have a more significant response to the negative correlation with the reservoir water level: Within 2 km of the reservoir, the response relationship is the best, gradually weaken in turn, and is almost marginal at and beyond about 7 km. Meanwhile, the analysis between seasonal rainfall and relative deformation also reflects that the reservoir water level is the main controlling factor of hillslope deformation in the reservoir area. In short, the reservoir water level parameter does not have spatial attributes that are reflected in space using the Pearson correlation coefficient, supplementing a new reference index for stability analysis of landslides in the reservoir area, which is of great value for risk analysis in the reservoir area.