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.