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

Abstract

AbstractThe 2021 Mw 7.3 Maduo earthquake ruptured the Kunlun Pass‐Jiangcuo fault (KPJF) in the Bayan Har Block (BHB) in northeastern Tibet. To explore the reasons behind the Maduo earthquake and the seismic hazards that followed this event in the BHB, we simulated the Coulomb stress changes before and after 2021 caused by 27 large historical earthquakes in the past centuries. We found that the Maduo earthquake was delayed for approximately 157 years because of the stress shadow resulting from fault interaction in the BHB. This stress shadow was mainly controlled by the 1937 Mw 7.5 earthquake on the Eastern Kunlun fault (EKLF) and the 1947 Mw 7.75 earthquake on the Dari fault. The stress shadow created by the Maduo earthquake covered several strike‐slip faults surrounding the Maduo earthquake rupture through negative feedback. Future seismic activity in the stress shadow zone may be delayed to a certain extent. Based on this finding, we propose that earthquakes on a fault might inhibit earthquakes on surrounding faults in parallel strike‐slip fault systems by creating a shadow zone in the BHB. This finding is important for understanding earthquake generation and migration in northeastern Tibet. It is also helpful for understanding the fault interactions in similar fault systems globally. The seismic hazards of the seismic gap to the west of the KPJF and the Maqin‐Maqu seismic gap on the EKLF increased after the Maduo earthquake. Therefore, attention should be paid to hazards prevention in these regions.