We derive the ALOS‐2 coseismic interferograms, pixel‐offsets and Sentinel‐2 sub‐pixel offsets of the 2023 M_w7.8 and M_w7.7 Kahramanmaras, Turkey earthquake sequence. Offset maps show that the sequence ruptured ∼300 km along the East Anatolian Fault (EAF) and ∼180 km along the secondary Cardak and Dogansehir faults. We infer the coseismic slip distribution and interseismic fault motion by inverting the co‐ and inter‐seismic observations. Inversion results show that the coseismic slip (∼8.0 m) and interseismic strike‐slip rate (∼4.6 mm/yr) on the main rupture of the M_w7.8 event are basically consistent with the ∼8.4 m and ∼3.9 mm/yr of the M_w7.7 event. Most coseismic slips of the M_w7.8 and M_w7.7 events occur within 10 and 12 km at depth, respectively, in keeping with the interseismic locking depth of 10.4 ± 3.3 km and 11.1 ± 3.1 km. This implies that the coseismic rupture kinematics correlate with the interseismic strain accumulation. Moreover, static stress changes show that the M_w7.7 event is likely promoted by ∼2 bar stress increase from the M_w7.8 event on the central section of its main rupture.

Interferometric synthetic aperture radar (InSAR) has become an important technique for studying earthquake cycle deformation. However, due to the limited satellite revisit time, it is often difficult to fully separate coseismic and postseismic slip from InSAR data. Nevertheless, accurately estimating spatiotemporal coseismic and postseismic fault slip distribution models is important for quantifying earthquake slip, understanding the kinematics of seismogenic faulting, and evaluating seismic hazards. Here, we develop a logarithmic model‐based method (LogSIM) for the joint inversion of coseismic and postseismic fault slip using InSAR data from multiple platforms in different orbits. This method considers the nature of early postseismic slip following logarithmic decay. The coseismic slip, the decay time constant, and the decay amplitude of the logarithmic model can be jointly estimated from unwrapped interferograms without the need for InSAR time series calculations, thereby reducing the number of unknown parameters and stabilizing the inversion. The robustness of LogSIM is first validated with synthetic experiments. We then apply LogSIM to invert for the coseismic and postseismic slip models of the 2017 Mw 7.3 Sarpol Zahāb earthquake. We find that the maximum afterslip value and postseismic moment release during the first four months reported in previous studies are underestimated by ~26% and ~31%, respectively, due to the unavailability of the first five days of postseismic deformation. The estimated afterslip distribution spatially overlaps with the aftershocks in the updip region of the fault plane. LogSIM could potentially be extended to integrate different space geodetic data in earthquake cycle deformation modeling.

Understanding the nature of foreshock evolution is important for earthquake nucleation and hazard evaluation. Aseismic slip and cascade triggering processes are considered to be two end-member precursors in earthquake nucleation processes. However, to perceive the physical mechanisms of these precursors leading to the occurrence of large events is challenging. In this study, the relocated 2021 Yangbi earthquake sequences are observed to be aligned along the northwest–southeast direction and exhibit spatial migration fronts toward the hypocenters of large events including the mainshock. An apparent static Coulomb stress increase on the mainshock hypocenter was detected, owing to the precursors. This suggests that the foreshocks are manifestations of aseismic transients that promote the cascade triggering of both the foreshocks and the eventual mainshock. By jointly inverting both Interferometric Synthetic Aperture Radar and Global Navigation Satellite Systems data, we observe that the mainshock ruptured a blind vertical fault with a peak slip of 0.8 m. Our results demonstrate that the lateral crustal extrusion and lower crustal flow are probably the major driving mechanisms of mainshock. In addition, the potential seismic hazards on the Weixi–Weishan and Red River faults deserve further attention.

Multi-temporal Interferometric Synthetic Aperture Radar (MT-InSAR) technique has proven to be a powerful tool for the monitoring of time-series ground deformations along the line-of-sight (LOS) direction. However, the one-dimensional (1-D) measurements cannot provide comprehensive information for interpreting the related geo-hazards. Recently, a novel method has been proposed to map the three-dimensional (3-D) deformation associated with underground fluid flows based on single-track InSAR LOS measurements and the deformation modeling associated with the Green’s function. In this study, the method is extended in temporal domain by exploiting the MT-InSAR measurements, and applied for the first time to investigate the 3-D time series deformation over Sebei gas field in Qinghai, Northwest China with 37 Sentinel-1 images acquired during October 2014–July 2017. The estimated 3-D time series deformations provide a more complete view of ongoing deformation processes as compared to the 1-D time series deformations or the 3-D deformation velocities, which is of great importance for assessing the possible geohazards. In addition, the extended method allows for the retrieval of time series of fluid volume changes due to the gas extraction in the Sebei field, which agrees well with those from the PetroChina Qinghai Oilfield Company Yearbooks (PQOCYs). This provides a new way to study the variations of subsurface fluids at unprecedented resolution.

The basaltic caldera volcanoes in the Galápagos Islands characteristically erupt lavas via summit circumferential and radial flank dike intrusions, but the underlying magma plumbing systems remain enigmatic. Here, we document surface displacements of Wolf volcano using interferometric synthetic aperture radar (InSAR) data from 2015 to 2022. We show that Wolf volcano experienced 6‐years of continuous inflation after the 2015 eruption, followed by a shallow flank eruption in January 2022. The deformation is modeled with a vertical caldera ring‐fault and a radial dike on the southeast flank. The ring‐fault underwent opening and reverse faulting during the inflation period, and closure and normal faulting during and after the eruption. Stress interactions between the ring‐fault and the flank dike suggest the asymmetric opening of the ring‐fault promotes flank eruptions. The best‐fit deformation model differs from the previous models and offers an alternative view of how magma is fed into radial dikes during flank eruptions.

On 17 June 2019, an Ms6.0 earthquake occurred in Changning, Sichuan, China (Changning event), which was the largest earthquake on record within 50 km of the area. It attracted great attention as the area has the largest shale gas production in China as well as significant mineral salt production. Using the Interferometric Synthetic Aperture Radar (InSAR), we extract the coseismic deformation of the Changning event and two earlier Ms > 5.0 earthquakes which occurred in the same region (16 December 2018 Ms5.7 and 3 January 2019 Ms5.3) from the Sentinel-1 and ALOS2 data. We use nonlinear and linear methods to invert the fault models of the three earthquakes based on the deformation fields. The final model shows that the Changning event was caused by a fault with left-lateral strike and thrust slip. The strike is 124.3° with a dip angle of 43.4°. The seismic moment obtained by inversion is 5.28 × 10¹⁷ Nm, corresponding to Mw 5.78. Based on the fault models, we analyze the cause of the Changning earthquake considering the local tectonic setting, Coulomb stress change, mining, and fluid injection. We consider that the event may be related to salt mining. The two earlier Ms > 5.0 earthquakes may also play an important role in advancing the Changning earthquake.