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Continental earthquakes, especially shallow earthquakes, can cause disasters in populated areas. On 20 May 2016, a moderate magnitude earthquake (Mw 6.0) ruptured on Northern Territory of Australia. With the aim of seismic hazard assessment, coseismic and postsesmic deformation of the Petermann earthquake has been determined using ALOS-2 ascending and Sentinel-1A descending images. The coseismic deformation field suggests that the earthquake ruptured in the NNW direction with a length of about 20 km, a rake angle of 57.1° and a moment magnitude of Mw 6.06. The maximum slip of 1.31 m can be observed at the depth of 1.25 km. The small baseline subset (SBAS) InSAR was utilized to obtain the postseismic deformation from 69 Sentinel-1A images in a descending orbit. The spatiotemporal evolution of the postseismic deformation presents a gradually decaying trend, with a maximum displacement of 5.4 cm within 858 days after the mainshock. Our afterslip model suggests that the maximum slip of 0.28 m occurred at the depth of 0.25 km with a slight shift to the northwest compared to the coseismic slip. The static Coulomb failure stress (CFS) changes at various depths were calculated, indicating the consistency between high loaded stress zones and aftershock distribution. [ABSTRACT FROM AUTHOR]

The extraction of high-accuracy co- and post-seismic deformation fields and inversions of seismic slip distributions is significant in the comprehension of seismogenic mechanisms. On 12 November 2017, a MW 7.3 earthquake occurred on the border between Iran and Iraq. To construct the co-seismic deformation field, Sentinel-1A synthetic aperture radar (SAR) images from three tracks were used. Based on a prior knowledge, least-squares iterative approximation was employed to construct the three-dimensional (3D) co-seismic deformation field. to derive a time series of 2D post-seismic deformation, the multidimensional small baseline subset (MSBAS) technique was use. Co-seismic deformation fields were asymmetric; the maximum relative displacement was nearly 90cm in the radar line-of-sight between two centers of co-seismic deformation. The 3D co-seismic deformation field showed southwestward horizontal motion and continuous subsidence-to-uplift variation from northeast to southwest. The two-dimensional (2D) post-seismic deformation time series showed a gradual decaying trend and good correspondence with the aftershock distribution. The main mechanism of post-seismic deformation was an afterslip of the post-seismic faults. We used the elastic half-space model to invert co-seismic deformation fields and obtain source parameters of the slip model. The maximum and average slips were 2.5 and 0.72 m, respectively. The average slip angle was 126.38° and the moment magnitude was MW 7.34. The results of this study will contribute to research on regional tectonic activities. [ABSTRACT FROM AUTHOR]

Large and shallow strike-slip earthquakes produce striking ground ruptures, damaging roads and infrastructure but providing great opportunities for examining the fault's structure. After the 2022 Mw 6.7 Menyuan earthquake, we observed abundant surface fractures by a combination of optical remote sensing, radar offset and unmanned aerial vehicle measurements. These fractures reveal a complex fault structure including apparent bending geometries and bifurcating branches, which are essential to understanding the mechanisms of faulting. In this paper, we used triangular dislocations to construct the fault geometry that reflected the distribution of measured strike changes but avoided unexcepted discontinuities and overlaps where the fault bent. The modeled fault geometry revealed an extensional releasing bend which was responsible for the southward branching of the fault rupture at its western edge. Our results also demonstrated the potential to explain the occurrence of aftershock clusters and to infer their fault geometries through the correlation analysis of the aftershock distribution and the slip induced stress field. The triangular dislocation model also enabled the calculation of the fault plane roughness and its spatial variation which directly controlled the fault slip magnitude and rupture termination. These analyses reveal an unprecedented level of detail of the fault structure and slip mechanics and, to some extent, offer insights into the physical processes and structural properties of crustal faults in the Earth's shallow crust. • Curved and branched surface ruptures were observed by multi-sourced geodetic data. • The fault structure was related to the distribution and clustering of aftershocks. • The fault rupture forked southward at its western end because of a releasing bend. • The fault plane roughness controlled the slip propagation and termination. [ABSTRACT FROM AUTHOR]