Coseismic Source Model of the February 2023 Mw 6.8 Tajikistan Earthquake from Sentinel-1A InSAR Observations and Its Associated Earthquake Hazard

On 23 February 2023, an Mw 6.8 earthquake struck the border of Tajikistan and Xinjiang China, the source mechanism remains controversial according to different seismic inversions. To better comprehend the source characteristics and the surface deformation pattern, we used the ascending and descending orbital Sentinel-1A SAR data to obtain the coseismic deformation of this earthquake based on the traditional two-pass differential interferometric synthetic aperture radar (InSAR). The source model is inverted from the InSAR coseismic deformation results. The possible Coulomb Failure Stress (CFS) transfer is analyzed based on the preferred source model. The results illustrate that the earthquake ruptured a blind left-lateral strike-slip fault of strike 28.1 & DEG; with a maximum slip of 1.53 m and the total geodetic moment is 1.99 x 10(19) N & BULL;m (Mw 6.83). The strike direction and the fault characteristics suggest the Seismogenic fault is a secondary fault of the Sarez-Karakul Fault System. The 2015 Mw 7.2 Sarez Earthquake plays a triggering role in the occurrence of the 2023 Tajikistan earthquake. Earthquake hazard on Sarez-Karakul Fault System and Sarez-Murghab Thrust System is enhanced due to the Coulomb stress loaded by the Tajikistan earthquake.

Automated summary

On 23 February 2023, a 6.8 magnitude earthquake occurred on the border of Tajikistan and Xinjiang China, with controversial source mechanism. By using SAR data from Sentinel-1A satellite, the coseismic deformation was obtained through the two-pass differential interferometric synthetic aperture radar (InSAR) technique. The source model was inverted based on the InSAR results, and the potential Coulomb Failure Stress (CFS) transfer was analyzed. The research suggests that this earthquake ruptured a left-lateral strike-slip fault, with a maximum slip of 1.53 m and a total geodetic moment of 1.99 x 10(19) N·m (Mw 6.83). The earthquake was triggered by the 2015 Mw 7.2 Sarez Earthquake, and it enhances the earthquake hazard on the Sarez-Karakul Fault System and Sarez-Murghab Thrust System due to Coulomb stress loading.