The 2022 Mw 6.7 Menyuan Earthquake Revealing High Stress Accumulation in the Western Section of the Tianzhu Seismic Gap

Abstract

The January 8th 2022 Menyuan earthquake(Mw6.7) occurred along major boundary fault zone in the north-eastern Tibetan Plateau. In this study, we derived the co-seismic deformation from pixel offset tracking (POT) and interferometric synthetic aperture radar (InSAR) by using Sentinel-1 data. The interferograms pattern shows that coseismic deformation is dominated by horizontal movements with the maximum displacement are over 0.5 m in both tracks and POT results. Then we inverted the geometry parameters of the causative fault and the slip distribution of the fault plane based on the finite dislocation model. The result shows the seismogenic fault has an average strike of 103.0^◦ and a northeast dip angle of 84^◦. moreover, the coseismic slip is primarily concentrated on the Lenglongling fault with on main asperity of 10 × 23 km and the maximum slip of 3.25 ± 0.34 m at depth of 4 km as well as rupture the eastern of the Tuolaishan fault with a small area of 5 × 5 km at depths of 0–8 km. On the basis of the dCFS results caused by historical earthquakes in Tuolaishan fault and geodetic-derived slip rate of the Tuolaishan fault, we emphasize the potential seismic risk on western Tianzhu gap is high.