On 28 March 2025, a moment magnitude ( M _w ) 7.8 earthquake ruptured a seismic gap along the Sagaing fault in Myanmar, generating a surface rupture 480 km in length and causing widespread damage. With holistic geodetic and seismic techniques, we resolved its rupture dynamics and fault zone structure. The rupture initiated as bilateral subshear and transitioned to supershear (~5.3 km/s) about 100 km south of the epicenter, sustaining this velocity for more than 200 km. The supershear segment aligns with a ~2-km–thick low-velocity fault zone exhibiting ~45% shear wave speed reduction. We suggest that the thick fault zone, aided by fault geometry and basin structure, enabled prolonged supershear propagation. Our findings emphasize that observations and models encompassing the entire fault zone are crucial for advancing both specific-event and earthquake-cycle simulations.

Coseismic off-fault deformation (OFD) measurements provide crucial insight into fault deformation behavior and shallow faulting damage. Although kinematic and dynamic characteristics of the causative faults associated with the 2023 Turkey-Syria earthquake doublet (Mw 7.8 and 7.6) were well determined, the OFD behavior and mechanism remain poorly constrained. Here we utilized high-resolution optical satellite geodesy to illuminate OFD distribution of the earthquake doublet. We found an average of ~80% and ~83% of coseismic fault deformation were localized on the primary fault planes of the Mw 7.8 and Mw 7.6 earthquakes, respectively; together, the remaining deformation manifested as OFD distributed within an average of 200-m- and 140-m-wide damage zones. Our observations revealed the OFD systematically increases in fault segments that have more complex geometry and slower coseismic rupture velocity, validating that both factors exhibit a significant facilitation on first-order variation of OFD during the earthquake doublet.

Focusing on stratified tropospheric delay correction in the small-amplitude coseismic displacement field of small-to-moderate earthquakes (<Mw 6.5), we develop a Simple-Stratification-Correction (SSC) approach based on the empirical phase-elevation relationship and spatial properties of the troposphere, via an equal-size window segmentation. We validate our SSC method using 23 real earthquakes that occurred from January 2016 to May 2021 with a moment magnitude (Mw) ranging from 4.5 to 6.5. We conclude that SSC performs well according to the amount of reduction in semi-variance and the root-mean-square value. This method primarily focuses on stratification delay correction; thus, it is especially useful in regions with complex terrain, while it can mitigate partial large-scale turbulence signals. We investigate three parameters that are empirically setup in the correction working flow and inspect their optimal settings, when implementing SSC for quick response after earthquake. Our method is ready to be integrated into an operational InSAR processing chain to produce a reliable atmospheric phase screen map, which can also serve as an auxiliary product to quickly and timely quantify stratification delays in coseismic interferograms. Through improved accuracy of the coseismic displacement field, the focal mechanism could be better constrained to facilitate the building and expansion of the geodesy-based earthquake catalogue.

The 2019 Ridgecrest, California earthquake sequence ruptured along a complex fault system and triggered seismic and aseismic slips on intersecting faults. To characterize the surface rupture kinematics and fault slip distribution, we used optical images and Interferometric Synthetic Aperture Radar (InSAR) observations to reconstruct the displacement caused by the earthquake sequence. We further calculated curl and divergence from the north-south and east-west components, to effectively identify the surface rupture traces. The results show that the major seismogenic fault had a length of ~55 km and strike of 320$°$ and consisted of five secondary faults. On the basis of the determined multiple-fault geometries, we inverted the coseismic slip distributions by InSAR measurements, which indicates that the Mw7.1 mainshock was dominated by the right-lateral strike-slip (maximum strike-slip of ~5.8 m at the depth of ~7.5 km), with a small dip-slip component (peaking at ~1.8 m) on an east-dipping fault. The Mw6.4 foreshock was dominated by the left-lateral strike-slip on a north-dipping fault. These earthquakes triggered obvious aseismic creep along the Garlock fault (117.3° W–117.5° W). These results are consistent with the rupture process of the earthquake sequence, which featured a complicated cascading rupture rather than a single continuous rupture front propagating along multiple faults.

Residual noise effect in interferometric synthetic aperture radar (InSAR) time-series data typically complicates the characterization of deformation behaviors on tectonic faults, especially postseismic deformation caused by multiple physical mechanisms. To reconstruct denoised postseismic deformation signal in noisy InSAR time-series (TSInSAR) data, we proposed a deep-learning-based neural network and trained it on noisy TSInSAR dataset, which was generated by adding Sentinel-1 TSInSAR noise onto synthetic postseismic deformation. The application results on experimental dataset validated that our neural network efficiently removed residual noise and automatically recovered clean postseismic deformation in noisy TSInSAR with any space and time sizes. Moreover, when applied to real TSInSAR data following the 2021 Maduo earthquake, our network provided accurate reconstructions of postseismic deformation in both time and space, demonstrating its generalization performance on actual data. In comparison with the original data, the denoised postseismic deformation exhibits greater consistency with the observations from a continuous global positioning system (cGPS). Interestingly, our denoised postseismic slip reveals spatial juxtaposition between the geometrically complex coseismic rupture segments and the heterogeneity of the early afterslip along the Maduo rupture. Overall, these successful applications highlight the network’s generalization performance to improve postseismic deformation signals.

The 2025 Mw 7.8 Myanmar earthquake ruptured the Sagaing fault, where sparse near-fault seismic observations limit source characterization. Here, we integrate optical imagery, InSAR, finite-fault slip inversion, back-projection (BP), and dynamic rupture simulations to investigate rupture kinematics and dynamics. Surface rupture extended for 472 km, with an average offset of 3.7 ± 0.4 m. Coseismic slip features no apparent shallow slip deficit. BP reveals southward supershear rupture ~30 s after nucleation. Calibrated with geodetic and seismic observations, dynamic rupture modeling indicates bilateral rupture initiation, with northward sub-shear propagation for 27 s at an average speed of 2.3 km/s. Southward rupture exhibits sub-shear (2.9 km/s) in 20 s, then transitions to sustained supershear (4.1‒5.9 km/s) over ~312 km in ~68 s, with its onset governed by the Burridge-Andrews mechanism and subsequently promoted by free-surface effects. These results reveal rupture complexity of this earthquake, emphasizing the need for improved near-fault observations in vulnerable regions.