Seismicity in the Northeastern Tibetan Plateau: Insights from Geodynamic Modelling

It is imperative to analyze, understand, and evaluate seismic hazards in the northeastern Tibetan Plateau due to the frequent strong earthquakes. In this study, we construct a three-dimensional viscoelastic finite element model to calculate the co- and post-seismic Coulomb stress changes caused by the regional historical strong earthquake sequence with M ≥ 7.0, spanning from 1561 to 1927. Our results indicate that preceding earthquake sequences cause a stress loading effect near the hypocenters of subsequent earthquakes, suggesting that the interaction between major earthquakes could be a crucial factor contributing to earthquake clusters. We then analyze the recurrence patterns of earthquakes within the regional fault system combined with the synthetic seismic catalog and the available regional seismic data. We find the recurrence intervals of earthquakes are unevenly distributed on different faults or different segments of the same fault. Finally, we analyze regional future seismic hazards combined with Coulomb stress changes and earthquake recurrence interval. Our assessment highlights that the elapsed time since the last strong earthquake on the Maomaoshan fault, Laohushan fault, western Tianqiaogou-Huangyangchuan fault, central Yunwushan fault, and southern Huanghe fault is approaching their respective recurrence intervals. Additionally, these regions have experienced marked Coulomb stress increases resulting from the historical earthquake sequence, indicating an elevated risk of future seismic activity on these faults. The numerical modeling here can provide scientific insights into the assessments of regional seismic hazard potential.