Dynamic source rupture process of the 2022 Menyuan Mw6.6 earthquake,Qinghai Province
Xie Zhangdi
Yu Xiangwei
Zhang Wenbo
Abstract：On January 8,2022,a significant earthquake with a magnitude of 6.6 struck Meny-uan,Qinghai,which resulted in substantial surface damage.To investigate the geological con-text behind the strong surface rupture generated by the Menyuan earthquake and its impact on the inhibition of stress release in the eastern section of the Tuolaishan fault,the spectral ele-ment method was employed in this study to simulate the dynamic rupture process of the branch-ing fault on actual terrain.The dynamic rupture simulation revealed that the rupture was initi-ated bilaterally along an upward direction from the initial rupture point.Under the influence of a high-speed P-wave anomaly located above the source area,the rupture displayed a non-conti-nuous pattern.With the progression of the rupture into the eastern section of Tuolaishan,a sig-nificantly abrupt decrease occurred in both slip rate and slip.Furthermore,the area with a slip rate of around 3.6 m/s near the surface of the Earth could be considered as a strong motion gene-ration zone.The combined influence of these factors,along with their high-frequency radi-ation,might have played a pivotal role in the pronounced coseismic surface deformation during the Mw6.6 earthquake in Menyuan.As calculated from the dynamic simulation results,the spatial distribution of strain suggested that the southwestern side of the eastern section of Tuolaishan and the northeastern side of the western section of Lenglongling experienced predominantly tensile stress,with corresponding areas subjected to compression.This observation aligns with the focal mechanism solution and the geological context of the northeastern margin of the Qing-hai-Tibet Plateau,where the direction of principal compressive stress transitions from north-south to southwest-northeast.Furthermore,the dynamic rupture process in the eastern section of Tuolaishan was strongly inhibited by the rupture of the branching fault.This led to incomp-lete stress release and a residual seismic magnitude of approximately MW5.1.Under the trigger of Coulomb stress from the Menyuan earthquake,further rupture in the future is possible.
Keywords：2022 Menyuan earthquakedynamic rupturespectral element methodCoulomb stress
Publication Date：2025-02-27
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：16( 21-36 )