InSAR stacking with atmospheric correction for rapid geohazard detection: Applications to ground subsidence and landslides in China

Abstract

Earth observation technologies have great potential in the investigation, monitoring and assessment of various geohazards. Stacking is an efficient InSAR method for estimating deformation rates and helps in the generation and update of the geohazard inventories. However, it relies on the assumption that the atmospheric statistics are stationary, which does not always hold in large-scale interferograms processing. The nonstationary signal, caused by turbulence and stratification of atmosphere, will bias the deformation estimate and lead to misinterpretations of the geophysical processes. In this paper, we propose an enhanced InSAR stacking method integrated with atmospheric correction. Atmospheric errors in the interferograms are first corrected, and then the mean deformation rate is estimated based on least squares. Applications are conducted in ground subsidence monitoring in the Yellow River Delta as well as landslide detection along the Jinsha River, China, with the deformation results evaluated by spatial structure function, semi-variogram and correlation. Spatial dependence in the subsidence results of the Yellow River Delta decreases from 757 km to 220 km, suggesting that the influence of atmospheric turbulence on deformation is mitigated. Correlation between deformation rate and elevation along the Jinsha River reduces from 0.40 to 0.15, indicating that stratification is suppressed. The proposed method adopts the strategies of simplicity and effectiveness, and the outcomes, which can meet the requirements of geohazards general survey, will be beneficial to rapid geohazard detection.