A central goal of laboratory seismology is to infer large-scale seismic processes from small-scale experiments, with acoustic emissions (AE) being a common observable. These signals, indicative of microfracturing, slip localization, and damage evolution, are often paralleled with earthquakes to understand seismic behaviors. This study challenges traditional perspectives by applying Coulomb rate-and-state seismicity theory, originally developed for earthquake clustering, to AE experiments. This theory maps stressing history to seismicity rates using rate-and-state friction, however, its validity under controlled experimental conditions remains an open question. We conducted four experiments on a sawcut sample of red felser sandstone, representing a fault under variable stress conditions. Adjustments in loading rates and initial conditions revealed that, while a single free parameter A—related to the direct effect—should suffice, a rescaling of the model by 1.5 to 2.2 was necessary for fitting the data. Differences in values across experiments appeared mostly non-systematic, and partial data usage did not yield consistently systematic parameter migrations. These findings suggest that fault microstructure may complexly alter parameter values during loading beyond what is accounted for in the Coulomb rate-and-state theory. Nonetheless, with the introduction of the scaling parameter, the Coulomb rate-and-state theory effectively captures the fundamental aspects of AE responses to complex controlled loading histories.

中文翻译：

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在声发射实验中应用和验证库仑速率和状态地震模型


实验室地震学的一个中心目标是从小规模实验中推断出大规模地震过程，其中声发射 （AE） 是一种常见的可观测对象。这些信号表明微压裂、滑移定位和损伤演变，通常与地震平行，以了解地震行为。本研究通过将最初为地震聚类开发的库仑速率和状态地震活动理论应用于 AE 实验，挑战了传统观点。该理论使用速率和状态摩擦力将强调历史映射到地震速率，但是，它在受控实验条件下的有效性仍然是一个悬而未决的问题。我们对红长针砂岩的锯切样品进行了四次实验，代表了可变应力条件下的断层。对加载速率和初始条件的调整表明，虽然与直接效应相关的单个自由参数 A 就足够了，但为了拟合数据，需要将模型重新缩放 1.5 到 2.2。实验之间的值差异似乎大多是非系统的，部分数据使用并没有产生一致的系统参数迁移。这些发现表明，断层微观结构可能会在加载过程中复杂地改变参数值，超出库仑速率和状态理论中所考虑的范围。尽管如此，随着缩放参数的引入，库仑速率和状态理论有效地捕获了 AE 对复杂受控载荷历史响应的基本方面。