Stress Transfer at the Northeastern End of the Bayan Har Block and Its Implications for Seismic Hazards: Insights From Numerical Simulations

Abstract

also occurred in the Bayan Har Block (Figure 1). This series of large earthquakes provide us with excellent examples for exploring the stress transfer and fault interactions of the strong earthquakes in the continent.The adjustment of the regional stress field by earthquakes includes a coseismic stress drop and viscoelastic stress transfer. Extensive research has confirmed that the stress relaxation in the viscoelastic lower crust and upper mantle transfers stress to the seismogenic layer in the upper crust (

Stress Evolution Before and After the 2021 Mw 7.3 Maduo Earthquake in Northeastern Tibet and Its Influence on Seismic Hazards

“…Our findings are congruent with those of Huang et al. (2021) and Zhu et al. (2021), who also calculated the ΔCFS of the KPJF caused by the 1937 Mw 7.5 (No.…”

“…Thus, the ΔCFS increase of 9 kPa in the Maqin-Maqu seismic gap was equivalent to tectonic loading for approximately 18-45 years. By calculating the stress change induced by the 2021 Maduo earthquake, we propose that future seismic hazards in the Maqin-Maqu seismic gap increased after 2021, which is consistent with the proposals of previous studies (He, Feng, et al, 2021;He, Wen, et al, 2021;Huang et al, 2021;Wang, Song, et al, 2021;Zhu et al, 2021). This finding helps explain the Mw 4.7 earthquake on 22 May 2021 (the day of the 2021 Maduo earthquake), which occurred in the center of the Maqin-Maqu seismic gap (Figure 6).…”

“…However, the postseismic stress change at the 2021 Maduo earthquake hypocenter reached −14 kPa during 1974–2021 (Figure 2l). Considering an inter‐seismic tectonic stressing rate of 0.8 kPa/a (Huang et al., 2021), a stress change of 14 kPa was equivalent to tectonic loading for approximately 18 years. This means that the negative ΔCFS(−14 kPa) at the 2021 Maduo earthquake hypocenter caused by the postseismic stress relaxation following the 1947 Mw 7.7.5 earthquake at least delayed the 2021 Maduo earthquake by approximately 18 years.…”

“…By considering the uncertainty from all cases by model parameterization, we found that the ΔCFS decrease at the 2021 Maduo earthquake hypocenter before 2021 ranged between −77 and −150 kPa. Given an inter‐seismic tectonic stressing rate of 0.8 kPa/a (Huang et al., 2021), the ΔCFS between 77 and 150 kPa was equivalent to tectonic loading for approximately 96–186 years. This means that the 2021 Maduo earthquake was significantly delayed for approximately 100–200 years because of the fault interaction between the EKLF, DRF, and KPJF in the BHB.…”

“…The inter-seismic Coulomb stress rate was estimated to be approximately 0.8 kPa/a at the Maduo earthquake hypocenter by Huang et al (2021) through numerical modeling stress in the lithosphere of the BHB. Given an inter-seismic tectonic stressing rate of 0.8 kPa/a (Huang et al, 2021), the ΔCFS (125.9 kPa) was equivalent to tectonic loading for approximately 157 years. Based on this finding, we suggest that 2021 Maduo earthquake was delayed by 157 years because of the stress shadow on the KPJF resulting from earthquake interactions in northeastern Tibet.…”