Decadal surface deformation induced by shale gas production in Weiyuan and its spatiotemporal correlation with microseismicity

As China’s second large-scale shale gas field, the Weiyuan field has undergone more than a decade of development, resulting in significant surface deformation. The combined effects of hydraulic fracturing, shale gas production, and regional tectonic activity complicate the interpretation of deformation patterns and their relationships with induced seismicity. In this study, long-term ground deformation in the western Weiyuan area from 2014 to 2024, corresponding to the period since the onset of shale gas exploitation, was systematically monitored using the small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) technique. The results indicate that ground deformation in the study area is predominantly concentrated east of the Molin Fault. Furthermore, time-cascaded principal component analysis (T-PCA) was applied for the first time to decompose the time-series InSAR-derived deformation in this region, enabling the extraction of spatiotemporal deformation patterns driven by different factors. In particular, deformation signals closely associated with shale gas exploitation were identified, and spatial differences in ground deformation caused by variations in development stages and initiation times across different shale gas production areas were revealed. These differences are difficult to distinguish using conventional time-series InSAR analysis alone. By integrating a microseismic event catalog, the spatiotemporal relationship between shale gas-related ground deformation and seismic activity was further investigated. The results show that areas experiencing significant deformation induced by shale gas exploitation correspond well spatially with zones of concentrated microseismicity. In addition, the time series of shale gas-related deformation exhibits an approximately sinusoidal variation with a period of about 2784 days, which is consistent with the timing of large-scale shale gas development. This pronounced temporal variability coincides with intensified exploitation activities and increased microseismic activity. The findings of this study provide new insights and a scientific basis for safer and more efficient shale gas development and for advancing the understanding of induced seismicity mechanisms.