Mechanical correlation of seismic activity in North China and its implications for future seismic risk

Fuqiang Shi, Hui Zhang, Zhigang Shao, Jing Xu, Huicheng Shao, Yujiang Li, Lingyun Ji, & Haidong Zhang

Published September 8, 2024, SCEC Contribution #13567, 2024 SCEC Annual Meeting Poster #205

North China is one of the regions in China with frequent strong earthquakes. According to historical records, it have been attacked by a series of extremely earthquakes, such as the 1303 Hongdong M≈8, 1556 Huaxian M＞8 and 1976 Tangshan M=7.8 earthquakes. Previous studies have shown that the seismic activity in North China displayed obvious temporal rhythmic characteristics. And this quasi-regular rhythmic character may be related to the coupling of the complex fault system in North China, which requires future work on sophisticated numerical simulation.
Using the Burgers rheological model which is more suitable for both long-term tectonic deformation and short-term postseismic deformation, we simulated the coseismic and postseismic Coulomb stress evolution that caused by all Ms≥6.5 earthquakes since 1303 in North China. Then, the Coulomb stress change associated with earthquakes during the same seismic activity period and across different seismic activity periods, are discussed based on the historical strong earthquake activity in North China and its temporal rhythmic character. The results indicated that the major seismic active areas in North China are controlled by the Coulomb stress loading of historical strong earthquakes, and its spatial migration in one seismic activity period should be driven by the Coulomb stress loading of the first Ms≥7.5 earthquake. The phenomenon of “Quiescence-Active warning-High activity-Surplus release” in the temporal seismic activity in North China could be interpreted as the dynamic response of the tectonic stress loading. Coulomb stress that associated with the rheological relaxation of the lithosphere contributes to the seismic activity in North China.
Based on the above analysis, we also compared the current seismicity with the Coulomb stress loading results and found that more than 85% M≥3 earthquakes since 1980 occurred in the stress loading areas. The result indicated that the small to moderate earthquakes in North China since 1980 should be stress controlled by the historical strong earthquakes.
The main purpose of our work is to discuss the Coulomb stress changes and their effects on the earthquakes activity in North China, and then furnish some references on the mechanism exploring of the spatial migration and temporal rhythmic character of the seismic activity in North China, as well as the related seismic risk analysis.

Key Words
Earthquake activity, Spatio-temporal evolution, Coulomb stress, Burgers rheology, North China

Citation
Shi, F., Zhang, H., Shao, Z., Xu, J., Shao, H., Li, Y., Ji, L., & Zhang, H. (2024, 09). Mechanical correlation of seismic activity in North China and its implications for future seismic risk. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Earthquake Forecasting and Predictability (EFP)