A Mw 6.6 earthquake struck Menyuan, Qinghai, China, on 7 January 2022. To determine the rupture parameters of this event, the coseismic InSAR deformation fields were mapped and further employed to estimate the focal mechanism. The best-fitting solution emphasized that the 2022 Menyuan earthquake ruptured at the junction of the Tuolaishan fault and the Lenglongling fault. Both rupturing faults were dominated by sinistral strike-slip, and the main slip was concentrated on the shallow part of the rupture plane. The latter was the main rupture segment with a strike of 106° and a dip of 86°. The slip mainly occurred at depths of 0–8 km, and the rupture was exposed at the surface. The maximum slip reached ~3.5 m, which occurred mainly at a depth of 4 km. Joint analysis of the optimal slip model, relocated aftershocks, Coulomb stress change, and field observation suggested that the strain energy in the Tuolaishan fault may not have been fully released and needs further attention. Moreover, the 2022 Mw6.6 Menyuan earthquake caused a significant stress loading effect on the western Tuolaishan fault and eastern Lenglongling fault, which implies that the 2022 event increased the seismic hazard in these regions.

The Qinghai–Tibet Railway is located on the Qinghai–Tibet Plateau and is the highest-altitude railway in the world. With the influence of human activities and geological disasters, it is necessary to monitor ground deformation along the Qinghai–Tibet Railway. In this paper, Advanced Synthetic Aperture Radar (ASAR) (T405 and T133) and TerraSAR-X data were used to monitor the Lhasa–Naqu section of the Qinghai–Tibet Railway from 2003 to 2012. The data period covers the time before and after the opening of the railway (total of 10 years). This study used full rank matrix small baseline subset InSAR (FRAM-SBAS) time-series analysis to analyze the Qinghai–Tibet Railway. Before the opening of the railway (from 2003 to 2005), the Lhasa–Naqu road surface deformation was not obvious, with a maximum deformation of approximately 5 mm yr⁻¹; in 2007, the railway was completed and opened to traffic, and the resulting subsidence of the railway in the district of Damxung was obvious (20 mm yr⁻¹). After the opening of the railway (from 2008 to 2010), the Damxung segment included a considerable area of subsidence, while the northern section of the railway was relatively stable. The results indicate that FRAM-SBAS technology is capable of providing comprehensive and detailed subsidence information regarding railways with millimeter-level accuracy. An analysis of the distribution of geological hazards in the Damxung area revealed that the distribution of the subsidence area coincided with that of the geological hazards, indicating that the occurrence of subsidence in the Damxung area was related to the influence of surrounding geological hazards and faults. Overall, the peripheral surface of the Qinghai–Tibet Railway is relatively stable but still needs to be verified with real-time monitoring to ensure that the safety of the railway is maintained.

Determining the relationship between crustal movement and faulting in thrust belts is essential for understanding the growth of geological structures and addressing the proposed models of a potential earthquake hazard. A Mw 5.9 earthquake occurred on 21 January 2016 in Menyuan, NE Qinghai Tibetan plateau. We combined satellite interferometry from Sentinel-1A Terrain Observation with Progressive Scans (TOPS) images, historical earthquake records, aftershock relocations and geological data to determine fault seismogenic structural geometry and its relationship with the Lenglongling faults. The results indicate that the reverse slip of the 2016 earthquake is distributed on a southwest dipping shovel-shaped fault segment. The main shock rupture was initiated at the deeper part of the fault plane. The focal mechanism of the 2016 earthquake is quite different from that of a previous Ms 6.5 earthquake which occurred in 1986. Both earthquakes occurred at the two ends of a secondary fault. Joint analysis of the 1986 and 2016 earthquakes and aftershocks distribution of the 2016 event reveals an intense connection with the tectonic deformation of the Lenglongling faults. Both earthquakes resulted from the left-lateral strike-slip of the Lenglongling fault zone and showed distinct focal mechanism characteristics. Under the shearing influence, the normal component is formed at the releasing bend of the western end of the secondary fault for the left-order alignment of the fault zone, while the thrust component is formed at the restraining bend of the east end for the right-order alignment of the fault zone. Seismic activity of this region suggests that the left-lateral strike-slip of the Lenglongling fault zone plays a significant role in adjustment of the tectonic deformation in the NE Tibetan plateau.

On 4 October 2023, a glacier lake outburst flood (GLOF) occurred at South Lhonak Lake in the northwest of Sikkim, India, posing a severe threat to downstream lives and property. Given the serious consequences of GLOFs, understanding their triggering factors is urgent. This paper conducts a comprehensive analysis of optical imagery and InSAR deformation results to study changes in the surrounding surface of the glacial lake before and after the GLOF event. To expedite the processing of massive InSAR data, an InSAR processing system based on the SBAS-InSAR data processing flow and the AI Earth cloud platform was developed. Sentinel-1 SAR images spanning from January 2021 to March 2024 were used to calculate surface deformation velocity. The evolution of the lake area and surface variations in the landslide area were observed using optical images. The results reveal a significant deformation area within the moraine encircling the lake before the GLOF, aligning with the area where the landslide ultimately occurred. Further research suggests a certain correlation between InSAR deformation results and multiple factors, such as rainfall, lake area, and slope. We speculate that heavy rainfall triggering landslides in the moraine may have contributed to breaching the moraine dam and causing the GLOF. Although the landslide region is relatively stable overall, the presence of a crack in the toparea of landslide raises concerns about potential secondary landslides. Our study may improve GLOF risk assessment and management, thereby mitigating or preventing their hazards.

A novel approach was developed to quantitatively examine land subsidence. It combines a new geophysical (NG) prospecting and the interferometric synthetic aperture radar (InSAR) technology to explore uneven development of land subsidence in Beijing, China. We derived land subsidence spatial information over 4 years (from November 2014 to July 2018) based on Sentinel‐1 satellite imagery and the small‐baseline InSAR (SBAS‐InSAR) method. Also, profile data were acquired using seismic frequency resonance (SFR) approach in a few settlement areas. We developed a geological model based on boreholes and SFR data. Thus, we can quantitively study the driving forces of a typical uneven land subsidence. We found that faults are controlling spatial developments of land subsidence in Beijing. The subsidence rates have different values along the same fault. Also, we revealed the contributions of compressible layers to the formation of uneven land subsidence.

Yangbajain contains the largest geothermal energy power station in China. Geothermal explorations in Yangbajain first started in 1976, and two plants were subsequently built in 1981 and 1986. A large amount of geothermal fluids have been extracted since then, leading to considerable surface subsidence around the geothermal fields. In this paper, InSAR time series analysis is applied to map the subsidence of the Yangbajain geothermal fields during the period from December 2011 to November 2012 using 16 senses of TerraSAR-X stripmap SAR images. In the case of the TerraSAR-X data, most orbital fringes were removed using precise orbits during the interferometric processing. However, residual orbital ramps remain in some interferograms due to the uncertainties in the TerraSAR-X orbits. To remove the residual orbital ramps, we estimated a best-fit ‘twisted plane’ for each epoch interferogram using quadratic polynomial models based on a network approach. This method removes most of the long-wavelength signals, including orbit ramps and atmospheric effects. The vertically stratified component (Topography Correlated Atmospheric Delay, TCAD) was also removed using a network approach. If the influence of seasonal frozen ground (SFG) is not taken into consideration, our results show that the subsidence rate around power plant I (the south plant) is approximately 20 mm/yr with a peak of 30 mm/yr. The subsidence rate around power plant II (the north plant) is approximately 10 mm/yr, when accounting for the influence of SFG on the power plant and its surrounding ground surface. Our results show that ground motion is caused by seasonal frozen ground and is strongly related to the temperature change.