A test on methods for Mc estimation and spatial-temporal distribution of b-value in the eastern Tibetan Plateau
Weicheng Gong, Huayuan Chen, Yajing Gao, Qing Li, Yunqiang Sun
Abstract
Seismic b- value is one of the most important parameters for seismological research and seismic hazards assessment, while the accuracy of the b- value largely depended on the completeness of seismic catalog. This article compares eight methods for estimating the minimum magnitude of completeness ( M c ). The results indicate that the modified maximum curvature method (MMAXC), exhibits greater stability and accuracy, closely approximating the standard M c obtained from the synthetic seismic catalogs. We then calculate the b- value using the instrumental seismic catalog from 2000–2023 in the eastern Tibetan Plateau. The results indicate that the five major earthquakes occur in regions with lower b- value. In addition, the temporal evolution of b- value before and after major earthquakes exhibits a common trend of decreasing before earthquakes, and increasing after earthquakes, which may reflect the stress accumulation and release during earthquakes. Combining the results of maximum shear strain rate and b- value, we identify five regions characterized by low b- value and high shear strain rate, indicating a higher potential seismic hazard in the future.