The ascending and descending InSAR deformations derived from ALOS-2 and Sentinel-1 satellite SAR images and GPS displacements are used to estimate the fault model of the 2018 Mw 6.4 Hualien earthquake. The sinistral strike-slip fault dipping to the west with a high dip angle of 89.4° and a rake angle of 201.7° is considered as the seismogenic fault of this event. This seismogenic fault also triggered the ruptures of the Milun fault, which dips to the east with a dip angle of ~72°, and an unknown west-dipping fault with a dip angle of 85.2°. Two predicted faulting models indicate that the InSAR deformation fields include more postseismic slip than those of the GPS data. The north segment of the Milun fault and west-dipping fault have been triggered by the rupture of the seismogenic fault, but the postseismic slip occurred only in the south segment of the Milun fault. The InSAR-derived co-seismic and postseismic faulting model suggests that the significant slip concentrates at depths of 2.4–15.0 km of the main fault, 0.0–14.0 km of the Milun fault. Only minor slip is detected on the west-dipping fault. The maximum fault slip of ca. 2.1 m is located at the depth of ca. 2.4 km under the Meilun Tableland. The Coulomb failure stress (CFS) change calculated by the co-seismic and postseismic faulting model shows that there is a significant CFS increase in the east of the south segment of the Milun fault, but few of the aftershocks occur in this area, which indicates a high risk of future seismic hazard.

The Dawanqi Oilfield in the Tarim Basin faces challenges such as declining pressure and surface deformation due to long-term extraction. Therefore, the recent long-term deformation characteristics of Dawanqi Oilfield and the driving factor quantification still need to be studied. Using Sentinel-1A Synthetic Aperture Radar (SAR) data (2021–2024) and Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technology, combined with multisource data and statistical analysis methods, we analyze deformation characteristics and driving factors in the Dawanqi Oilfield. Results show line of sight (LOS) deformation rates of −21 to 24 mm/year, with the oilfield reaching 24 mm/year, significantly higher than in other areas. Seasonal deformation peaks at 17.37 mm, with the oilfield and farmland being highly sensitive. The Mann-Kendall test reveals 48.42% significant subsidence and 28.95% uplift. Hurst exponent analysis indicates 99% of the areas show an antipersistent trend, but the oilfield’s persistent deformation (Hurst >0.5) will likely continue. Principal component analysis confirms oil extraction as the main driver (PC1 variance: 90.47%), whereas natural factors such as rainfall and groundwater have minimal impact (|r|<0.15). These findings support safe oilfield development and validate SBAS-InSAR’s effectiveness in arid, complex environments.

High-intensity mining leads to severe ground deformation and secondary geological disasters in coal mines. Persistent Scatters Synthetic Aperture Radar Interferometry (PSInSAR) has strong deformation monitoring capability, but cannot detect enough target points in the mining core and surrounding low-coherence areas. This paper attempts to combine Distributed Target (DT) and Slowly-decorrelating Filtered Phase Target (SDFPT) to improve the density and coverage of deformation monitoring points in mining areas. The Fast Statistically Homogenous Pixel Selection (FaSHPS) and the amplitude dispersion index method were used to select DT and SDFPT candidate points, respectively. Then phase optimization and stability analysis were carried out for the two types of points, and the qualified DT and SDFPT were screened out. Both kinds of points were then fused, and three-dimensional phase unwrapping was performed. The phase time series were recovered. The spatiotemporal filtering was performed, and the deformation time series and the annual average deformation rate of the fused point set were finally obtained. The 60-scenario Sentinel-1 images covering the Buertai Coal Mine acquired from April 2018 to April 2020 were selected for deformation monitoring. The results show that the density and coverage of deformation points are significantly improved after the fusion of DT and SDFPT, and the maximum deformation level that can be monitored is also increased. There are 5 deformation funnels in the experimental area, and the maximum cumulative deformation reaches -309.76 mm. The influence range of deformation and the difference between time series deformation in different years are highly correlated to mining activities in mining areas.

Severe subsidence poses a significant threat to coastal river deltas, bringing substantial hazards. The Yellow River Delta, being the youngest of such deltas, is particularly vulnerable due to its unstable sedimentary structure. It has experienced significant subsidence as a result of frequent human activities. The InSAR technology facilitates large-area, long-term deformation monitoring of the Yellow River Delta region. Current research has identified that subsidence in the Yellow River Delta is primarily influenced by groundwater extraction and oil exploitation. However, there is a lack of comprehensive study on the spatiotemporal patterns of subsidence induced by different human activities. To acquire extensive and long-term surface subsidence information in the Yellow River Delta region and analyze its causes, this study utilizes 92 ascending Sentinel-1 satellite images and 79 descending Sentinel-1 satellite images. Applying the SBAS-DInSAR technique, the research investigates ground subsidence in the area from January 2019 to April 2022. The study includes an integration of interferometric fringes and DInSAR deformation monitoring results, along with ascending and descending orbit deformation rates for internal accuracy cross-checking. Additionally, it examines the spatiotemporal evolution characteristics and causes in different human-impacted areas. The results indicate that the deformation rates from ascending and descending orbits show high consistency, with a correlation coefficient exceeding 0.8. Significant subsidence areas in the Yellow River Delta are concentrated in the eastern coastal regions, with the maximum subsidence rate reaching approximately -255 mm/year. The primary human-induced factors contributing to subsidence include the extraction of underground brine, oil, and groundwater. Additionally, natural factors like temperature, precipitation, and evaporation also impact subsidence. Notably, the deformation rate changes induced by precipitation exhibit a delayed response. Human activities, with their varying types and intensities, impart distinct temporal characteristics to subsidence. In areas like wetlands, urban regions, and farmlands, deformation is influenced by changes in groundwater levels, resulting in smaller deformation magnitudes and fluctuating deformation rates affected by variations in rainfall, temperature, and evaporation. Oil extraction deformation exhibits long-term change characteristics, influenced by the volume of oil extracted and water injection; from January 2019 to July 2020, a subsidence trend was observed, followed by a slow rebound after July 2020. Subsidence induced by groundwater extraction is characterized by rapid and stable deformation rates. Temporally, significant linear rate subsidence occurred from January to August 2019, with varying degrees of rebound from June 2019 to March 2020, followed by a return to subsidence. Influenced by heavy rainfall, there is a minor rebound each year from July to August.