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.

本数据集与Giorgetti, C. 和 Violay M. 在《GRL》发表的论文《荷载路径对断层复活的影響：实验室视角》（The Influence of Loading Path on Fault Reactivation: a Laboratory Perspective）密切相关。该研究论文的DOI为https://doi.org/10.1029/2020GL091466。数据文件包含了在研究论文中报告的实验过程中收集的原始数据。

摘要：在评估断层复活的潜力和相关的地震风险时，通常忽视断层所经历的荷载路径。然而，应力历史会影响断层带的压缩和膨胀，进而影响其力学性质。因此，在可能发生膨胀或压缩的粘性断层核中，荷载路径的作用不容忽视。在本研究中，我们在实验室中重现了不同构造荷载路径，包括正反转断层（无显著流体压力增加时的荷载强化）和正常断层带摩擦断层（荷载弱化），以探究荷载路径对断层复活和地震潜能的影响。我们发现，在复活之前，实验中的反转断层经历压缩，而实验中的正常断层经历膨胀。此外，在可比的正常应力下复活时，正常断层比反转断层更容易发生地震滑动。我们推断，较高平均应力的正常断层在压缩断层岩石方面更为有效，从而增加了其刚度并有利于地震滑动。

通俗易懂的摘要：地球壳层中预先存在的断层沿线的滑动，发生在剪切应力在断层平面上的解算值超过其摩擦强度时，有可能引发灾难性的地震。剪切应力的增加可以遵循不同的构造荷载路径，特别是当与正常应力夹紧断层的降低与增加相对应时，分别为荷载弱化和荷载强化路径。荷载路径的作用不容忽视，尤其是在存在厚度较大、粘性断层带且在不同应力条件下可以改变其体积的情况下。然而，在大多数摩擦实验中，断层是在恒定或增加的正常应力下加载的，即荷载强化。在此，我们填补了实验室荷载路径模拟复活时在相同的正常应力夹紧断层但具有不同构造应力历史的空白。有趣的是，我们的结果表明，对于荷载强化和荷载弱化路径，水力-机械行为存在对比：1）在复活之前，断层带的压缩与膨胀；2）在可比的正常应力下复活时，稳定的蠕变与地震滑动。我们的研究仅触及荷载路径对厚断层稳定性和对断层带中流体循环潜在影响的可能性，强调了进一步研究荷载路径影响的重要性。