Co‐ and Post‐Seismic Mechanisms of the 2020 Mw 6.3 Yutian Earthquake and Local Stress Evolution

Abstract

The epicenter (35.596°N, 82.379°E, USGS) is located in the northwest of the Qinghai-Tibet Plateau, within the tectonic junction area (Figure 1) formed by the Kangxiwar fault, Longmu Co-Bangda Co fault, and the southwestern section of the Altyn Tagh fault (Elliott et al., 2010;He et al., 2020;Xu et al., 2013). An Ms 4.7 foreshock preceded the mainshock, and no aftershocks above Ms 4.5 were observed in the area after the mainshock (Luo et al., 2021). Different seismological agencies (such as USGS, GCMT, GFZ, IPGP, etc.) agreed that the earthquake was a normal faulting event (Table 1) with a nearly north-south fault strike.

Source Models of the 2016 and 2022 Menyuan Earthquakes and Their Tectonic Implications Revealed by InSAR

“…The rise of deep Coulomb stress caused by shallow coseismic rupture could trigger deep aftershocks, release accumulated stress, and reduce the risk of future strong earthquakes. Alternatively, the loading of deep faults due to these stress changes could cause further stress concentration, increasing the risk of future strong earthquakes [ 31 , 55 ]. The aftershocks of the 2022 event concentrated primarily at 10 km ( Figure 1 c), with some aftershocks reaching the depth of the 2016 event.…”