发表机构
University of Chinese Academy of Sciences; Harvard University（中国科学院大学; 哈佛大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过分析中国大陆50余年地震记录，比较经典b值与b-positive值在主要构造区的时空演化，发现b-positive受检测能力影响更小，且低b值斑块与中强地震破裂区吻合，为b值前兆监测奠定基础。
AI 中文摘要
Gutenberg-Richter幂律关系本质上控制着地震活动的频率-震级分布（FMD）。b值作为该分布的斜率，不仅被广泛认为是小事件与大事件相对比例的量化指标，而且被视为地壳差应力及潜在大地震到巨大地震的诊断性前兆。本研究调查了中国大陆主要构造区域（例如川滇、华北和西北地区）b值的时空演化。我们对超过50年的地震记录进行分析，系统考察了中国大陆主要发震带b值的变化，以评估其作为中强地震前兆的效用。此外，我们的比较表明，在所考察的案例中，b-positive估计器比经典b值估计器受检测能力变化和短期余震不完整性的影响更小。虽然川滇地区呈现出高、低b值复杂“镶嵌”模式，反映了流体驱动过程和局部闭锁，但华北平原和西北地区则表现出持续较低的b值，暗示高背景应力和刚性完整地壳。我们还发现，目录中若干中大型地震的破裂区域与早期长期时间窗中识别的局部低b值斑块相吻合。本研究为在中国大陆系统性地、前瞻性地评估基于b值的前兆监测提供了基础。
英文摘要
The Gutenberg-Richter power-law relationship essentially governs the frequency-magnitude distribution (FMD) of seismic activity. The b-value, as the slope of this distribution, is widely recognized not only as a quantifier of the relative proportion of small to large events but also as a diagnostic precursor of crustal differential stress and potential big to huge earthquakes. This study investigates the spatiotemporal evolution of b-values across major tectonic regions in mainland China, for instance, the Sichuan-Yunnan, North China, and Northwest regions. Our analysis of over 50 years of seismic records systematically examines b-value variations across major seismogenic zones in mainland China to evaluate their utility as precursors for moderate-to-strong earthquakes. Moreover, our comparison suggests that the b-positive estimator is less affected by changes in detection capability and short-term aftershock incompleteness than the classical b-value estimator in the cases examined. While the Sichuan-Yunnan region displays a complex "mosaic" of high and low b-values reflecting fluid-driven processes and localized locking, the North China Plain and Northwest regions exhibit consistently lower b-values, suggesting high background stress and rigid crustal integrity. We also find that several of the rupture areas of moderate-to-large earthquakes in our catalog coincide with localized low-b patches identified in earlier long-term windows. This study provides a foundation for systematic, prospective evaluation of b-value-based precursor monitoring in mainland China.
