Xin Qiao

Quantifying fault frictional properties is fundamental to understanding slip behavior and seismic hazard. We analyze 2 years of Sentinel‐1 SAR data following the 2023 Turkey earthquake doublet using Independent Component Analysis‐enhanced Small Baseline Subset‐InSAR, to resolve postseismic deformation and invert for afterslip on the East Anatolian and Çardak faults. Within a rate‐and‐state framework, we estimate the friction parameter in postseismically stable regions ( R ² > 0.9), showing that afterslip dominantly occurs in high velocity‐strengthening regions, whereas coseismic rupture and aftershocks cluster near low zones or adjacent unstable patches. Depth‐dependent slip partitioning indicates a brittle–ductile transition modulated by frictional heterogeneity, and eastward migration of deep afterslip and segmentation of slip behavior highlight postseismic deformation complexity. Elevated values on the Pütürge segment indicate rupture propagation was limited by velocity‐strengthening regions. These results suggest that frictional heterogeneity likely governs slip partitioning and provide quantitative constraints for seismic hazard assessment in continental fault systems.

The 2025 destructive Myanmar earthquake ruptured the previously recognized seismic gap along the Sagaing fault, with the longest ever recorded surface ruptures (500 km). Here, we use SAR and optical images to characterize coseismic and early postseismic deformation of this event. North‐south displacements delineate the extent of surface ruptures, which are confined between historically ruptured regions, supported by dramatic slip reductions along the strike near the two rupture terminations. Coseismic slip model suggests two high‐slip zones of distinct sizes separated by a low‐slip zone. Coseismic slip has peak values at the surface almost all along the rupture, suggesting an absence of shallow slip deficits. Early postseismic deformation over 1 month after the event is obtained by optical horizontal offsets. Rapid shallow afterslip (5 cm/day) is only found along the southern segment, with some spatial overlap with coseismically slipped zones indicating frictional heterogeneity of the Sagaing fault.

The 2025 7.0 Dingri earthquake, which struck southern Tibet on 7 January 2025, provides kinematic insights into extensional tectonics in the region. We use Sentinel‐1 and Lutan‐1 Synthetic Aperture Radar (SAR) data sets to analyze the coseismic displacement fields of this event. Our analysis reveals that this event ruptured two conjugate normal faults, likely two boundary faults of a graben structure in the extensional rift. Our best‐fitting slip model includes a large west‐dipping fault and a secondary east‐dipping fault, both characterized by dominant normal slip but with distinct slip amplitude. Relocated aftershocks also reveal that the slip along the secondary east‐dipping fault occurred coseismically rather than postseismically. Fault geometry, kinematics and geomorphology jointly imply the young, immature graben in the southern Xainza‐Dinggye rift. Boundary faults accommodate extensional strain jointly, which is likely the common mode of strain accommodation in the region.

Large‐scale geodetic measurements of crustal deformation in the north‐central Tibetan Plateau are crucial for improved understanding of earthquake‐cycle processes and long‐term seismic hazard assessment. We use GPS velocities and Interferometric Synthetic Aperture Radar (InSAR) observations (2015–2020) on eight descending and eight ascending Sentinel‐1 tracks to map surface motions and their gradients for an area of over ∼2,000 km × 350 km around the Kunlun‐Manyi fault system. The derived line‐of‐sight (LOS) and 3D velocity fields demonstrate ongoing postseismic transients along the ruptured segments of the 1997 Manyi and 2001 Kokoxili earthquakes, interseismic deformation along locked fault segments, and strain accumulation on a large subsidiary fault (i.e., the Kunlun Pass fault). We use elastic dislocation and analytical postseismic deformation models constrained by our dense InSAR measurements to quantify the interseismic and postseismic contributions, which reveal the along‐fault distribution of fault slip rate and locking depth along the entire length of the fault. The results indicate that the slip rate of the Kunlun fault systematically decreases toward the west to the west of the Taiyang Lake fault. We also find that the interseismic strain accumulation rate along the main trace of the Kunlun fault is to first‐order spatially constant (0.1–0.15 microstrain/yr), except around its restraining bend. As the historically unruptured segments, especially the eastern segments (from 95°E to 101°E) of the Kunlun fault, have relatively fast slip rates and high locking depths (>15 km), they have the potential to generate large and damaging earthquakes in this region.

The Haiyuan fault zone is an important tectonic boundary and strong seismic activity belt in northeastern Tibet, but no major earthquake has occurred in the past ∼100 years, since the Haiyuan M8.5 event in 1920. The current state of strain accumulation and seismic potential along the fault zone have attracted significant attention. In this study, we obtained the interseismic deformation field along the Haiyuan fault zone using Envisat/ASAR data in the period 2003–2010, and inverted fault kinematic parameters including the long-term slip rate, locking degree and slip deficit distribution based on InSAR and GPS individually and jointly. The results show that there is near-surface creep in the Laohushan segment of about 19 km. The locking degree changes significantly along the strike with the western part reaching 17 km and the eastern part of 3–7 km. The long-term slip rate gradually decreases from west 4.7 mm/yr to east 2.0 mm/yr. As such, there is large strain accumulation along the western part of the fault and shallow creep along the Laohushan segment; while in the eastern section, the degree of strain accumulation is low, which suggests the rupture segments of the 1920 earthquake may have been not completely relocked.

The 2015 Mw 7.8 Gorkha, Nepal, earthquake occurred in the central Himalayan collisional orogenic belt, which demonstrated complex fault kinematics and significant surface deformation. The coseismic deformation has been well documented by previous studies using Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data. However, due to some limitations of spatially sparse GPS stations and InSAR only-one-dimensional observation in the line-of-sight (LOS) direction, the complete distribution and detailed spatial variation of the three-dimensional surface deformation field are still not fully understood. In this study, we reconstructed the three-dimensional coseismic deformation fields using multi-view InSAR observations and investigated the refined surface deformation characteristics during this event. We firstly obtained four ascending and descending InSAR coseismic deformation maps from both Sentinel-1A/B and ALOS-2 data. Secondly, we obtained the synthetic north-south deformation field from our best-fitting slip distribution inversions. Finally, we calculated three-dimensional deformation fields, which were consistent with coseismic GPS displacements but with higher resolution. We found that the surface deformation is dominated by horizontal southward motion and vertical uplift and subsidence, with minor east-west deformation. In the north-south direction, the whole deformation area reaches at least 150 × 150 km with a maximum displacement of ~1.5 m. In the vertical direction, two areas, including uplift in the south and subsidence in the north, are mapped with a peak displacement of 1.5 and −1.0 m, respectively. East-west deformation presented a four-quadrant distribution with a maximum displacement of ~0.6 m. Complex thrusting movement occurred on the seismogenic fault; overall, there was southward push motion and wave-shaped fold motion.