• ISSN 2097-1893
  • CN 10-1855/P

地震动静态触发机制与时空特征研究进展

Advances in the spatiotemporal characteristics and mechanisms of earthquake static and dynamic triggering

  • 摘要: 地震产生的动、静态应力变化可能进一步触发周边甚至远场断层发生地震,称为地震的动态和静态触发,研究这一物理过程对于地震预测和风险评估具有重大意义,因而成为近三十余年来学界持续关注和研究的重要领域. 然而,如何有效区分动、静态二种触发模型在近场的触发作用贡献,以及如何解释动态触发的延时现象,则成为争论的焦点. 对此,本文通过综合前人在相关领域的主要研究,得出以下主要结论:①静态触发是近场触发的主导机制,动态触发则在一定条件下可作为静态触发的补充机制,在满足特定的优势条件下参与近场触发. ②可以采用库仑破裂模型与R-S Law两种模型模拟静态应力变化触发地震的发震时刻提前量,所得结果既具有一阶近似性,也具有二阶差异性. ③动态延时触发现象则不能为传统的库仑破裂模型和R-S Law所解释,只能依照所处断层区域环境的不同,被不同物理过程(如流体作用等)和模型所解释,但最终往往仍需借由静态应力变化的作用来实现. ④无论是理论模拟还是实验研究,都反映了动态触发的局限性,广泛观测到的动态触发现象所依赖的核心优势条件是动态应力变化幅度足够大或断层处于趋于破裂的极限状态(低有效正应力或临近构造加载的破裂极限);断层在何种程度上趋近于破裂极限状态,以及区域构造环境的不同(比如是否有沉积层)决定了不同地区动态触发阈值的大小;影响地震触发的因素还包括地震波频率,但地震波频率与动态触发阈值的相关性比较复杂,仍有较大争议. ⑤此外,本文也讨论了人工注入流体诱发地震、地球固体潮触发地震和慢滑移事件的触发等现象,认为这些现象的触发规律与前述结论相适应.

     

    Abstract: The static and dynamic stress changes induced by earthquakes can further trigger seismic events on surrounding or even remote faults. This phenomenon, known as static and dynamic triggering of earthquakes, has significant implications for earthquake prediction and seismic hazard assessment. Consequently, it has remained a focal point of seismological research over the past three decades. However, key challenges persist in effectively distinguishing the relative contributions of static and dynamic triggering mechanisms in near-field seismic triggering, as well as in explaining the phenomenon of delayed dynamic triggering. In this study, we synthesize the main findings from prior research in the field and present the following conclusions: ①Static triggering is the dominant mechanism in near-field earthquake activation, while dynamic triggering serves as a supplementary mechanism under certain favorable conditions. When specific thresholds are met, dynamic stress changes can participate in near-field triggering. ②The Coulomb failure model and rate-and-state (R-S) friction law can be employed to simulate the advance of earthquake nucleation timing caused by static stress changes. The results exhibit both first-order agreement and second-order discrepancies, reflecting model-dependent nuances. ③The delayed nature of dynamic triggering cannot be adequately explained by conventional Coulomb failure models or the R-S law. Instead, such phenomena must be interpreted through different physical processes—such as fluid-related mechanisms—depending on the geological context of the fault zone. Nevertheless, the eventual occurrence of seismic events often still necessitates the contribution of static stress perturbations. ④Both theoretical modeling and laboratory experiments highlight the limitations of dynamic triggering. Observed dynamic triggering phenomena are generally contingent upon two key factors: sufficiently large amplitudes of dynamic stress changes and fault conditions approaching the critical state of failure (e.g., low effective normal stress or proximity to tectonic loading thresholds). The degree to which a fault nears failure and the regional tectonic environment (such as the presence of sedimentary layers) jointly determine the threshold required for dynamic triggering in a given area. Additionally, while seismic wave frequency is known to influence triggering potential, its relationship with dynamic triggering thresholds remains complex and contentious. ⑤Additionally, this paper discusses phenomena such as fluid injection-induced seismicity, solid Earth tide-triggered earthquakes, and the triggering of slow slip events. It is argued that the triggering mechanisms of these phenomena are generally consistent with the above conclusions.

     

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