Dataset for: The Influence of Loading Path on Fault Reactivation: a Laboratory Perspective

This dataset is related to the research paper "The Influence of Loading Path on Fault Reactivation: a Laboratory Perspective" by Giorgetti, C., & Violay M., in GRL. https://doi.org/10.1029/2020GL091466 The files contain the raw data collected during the experiments that are reported in the research manuscript. Abstract: The loading path the fault experiences is often neglected when evaluating its potential for reactivation and the related seismic risk. However, stress history affects fault zone compaction and dilation, and thus its mechanics. Therefore, in incohesive fault cores that could dilate or compact, the role of the loading path could not be ruled out. Here we reproduce in the laboratory different tectonic loading paths for reverse (load‐strengthening in the absence of significant fluid pressure increase) and normal gouge‐bearing faults (load‐weakening) to investigate the loading path influence on fault reactivation and seismic potential. We find that, before reactivation, experimental reverse faults undergo compaction, whereas experimental normal faults experience dilation. Additionally, when reactivated at comparable normal stress, normal faults are more prone to slip seismically than reverse faults. We infer that the higher mean stress normal faults experience compacts more efficiently the fault rock, increasing its stiffness and favoring seismic slip. Plain Language Summary: Slip along pre‐existing faults in the Earth’s crust occurs whenever the shear stress resolved on the fault plane overcomes its frictional strength, potentially generating catastrophic earthquakes. The increase in the shear stress can follow different tectonic loading paths, and in particular, load‐weakening versus. load‐strengthening paths when it is coupled respectively to a decrease versus. an increase in the normal stress clamping the fault. The role of the loading path cannot be ruled out, especially in the presence of a thick, incohesive fault zone that can change its volume under different stress conditions. However, in most friction experiments, the fault is loaded under constant or increasing the normal stress, that is, load‐strengthening. Here, we bridge the gap in laboratory loading paths simulating reactivation at the same normal stress clamping the fault but with different tectonic stress histories. Interestingly, our results suggest contrasting hydro‐mechanical behavior for load‐strengthening versus. load‐weakening path: (1) before reactivation, fault zone compaction versus. dilation and (2) when reactivated at comparable normal stress, stable creep versus seismic slip, respectively. Our study has only scratched the surface of the loading‐path influence on thick fault stability and potential implications for fluid circulation in fault zones, stressing the importance of further investigating the loading path influence.

本数据集关联Giorgetti C.与Violay M.发表于《地球物理研究通讯》(Geophysical Research Letters, GRL)的论文《加载路径对断层再活化的影响：实验室视角》（*The Influence of Loading Path on Fault Reactivation: a Laboratory Perspective*），DOI链接为https://doi.org/10.1029/2020GL091466。数据集内包含该研究论文中报道的实验原始采集数据。

摘要：在评估断层再活化潜力及相关地震风险时，断层所经历的加载路径常被忽视。然而，应力历史会影响断层带的压实与扩容，进而影响其力学特性。因此，对于可能发生扩容或压实的非黏结断层核部，加载路径的影响不容忽视。本研究在实验室中针对逆冲断层（无显著流体压力升高时的加载强化型）及含断层泥（fault gouge）的正断层（加载弱化型）复现了不同的构造加载路径，以探究加载路径对断层再活化及地震潜能的影响。研究发现，在再活化前，实验逆冲断层发生压实作用，而实验正断层则出现扩容现象。此外，当在相近正应力条件下发生再活化时，正断层比逆冲断层更易发生地震型滑动。我们推断，正断层所承受的更高平均应力可更高效地压实断层岩，提升其刚度并促进地震滑动。

通俗解读摘要（Plain Language Summary）：地壳中预先存在断层的滑移，发生于断层平面所受剪切应力超过其摩擦强度之时，可能引发灾难性地震。剪切应力的增加可遵循不同的构造加载路径，具体而言，当分别与夹持断层的正应力降低、升高耦合时，对应加载弱化与加载强化路径。加载路径的影响不容忽视，尤其是在存在可随不同应力条件改变体积的厚层非黏结断层带的情况下。然而，多数摩擦实验中，断层均在恒定或升高的正应力下加载，即加载强化路径。本研究填补了实验室加载路径研究的空白，模拟了在夹持断层的正应力相同但构造应力历史不同的条件下的断层再活化过程。有趣的是，研究结果显示加载强化与加载弱化路径呈现出截然相反的水力-力学（hydro-mechanical）行为：（1）再活化前，断层带分别表现为压实与扩容；（2）在相近正应力条件下再活化时，分别对应稳定蠕滑与地震型滑动。本研究仅初步探索了加载路径对厚层断层稳定性的影响，以及其对断层带流体循环的潜在意义，强调了进一步探究加载路径影响的重要性。