Fault Geometry and Mechanism of the Mw 5.7 Nakchu Earthquake in Tibet Inferred from InSAR Observations and Stress Measurements

Different types of focal mechanism solutions for the 19 March 2021 Mw 5.7 Nakchu earthquake, Tibet, limit our understanding this earthquake’s seismogenic and geodynamic process. In study, coseismic deformation field was determined geometric parameters fault were inverted via Interferometric Synthetic Aperture Radar (InSAR) processing Sentinel-1 data. The inversion results show that earthquake are 237°/69°/?70° (strike/dip/rake), indicating is a NEE-trending, NW-dipping dominated by normal faulting with minor sinistral strike-slip components. regional tectonic stress derived from in-situ measurements shows orientation maximum principal compressive around epicenter NNE, subparallel to strike, which controlled dominant faulting. occurrence seven M ? 7.0 historical earthquakes since Shenza in 1934 caused increase 1.16 × 105 Pa at hypocenter, significantly advanced earthquake. Based on comprehensive analysis fields mechanisms we propose occurs accommodate NE-trending compression Indian Plate Eurasian strong hastened These provide theoretical basis geometry mechanics produced