河海大学土木与交通学院学术报告会之一百六十七
题 目：岩石断层/裂缝的前兆预移、破裂传播与摩擦滑移：加载速率与围压的影响
报告人：王磊，德国地学研究中心GFZ助理研究员
时 间：2025年4月2日（周三）9:30-11:30
地 点：科学馆516会议室
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河海大学土木与交通学院
2025年4月1日
报告人简介：
王磊博士，德国地学研究中心GFZ助理研究员。2021至今，在德国地学研究中心GFZ 4.2部门 ‘Geomechanics and Scientific Drilling’任助理研究员。主要研究领域包括颗粒材料孔弹力学以及微观力学，断裂力学，岩石摩擦学，流体注入诱发地震以及声发射分析。目前已发表SCI论文22篇，其中以一作/通讯作者在综合性期刊PNAS，地球物理期刊EPSL，GRL， JGR-Solid Earth ，材料学期刊Acta Materialia以及岩土力学期刊RMRE、Acta Geotechnica等发表论文11篇。二篇ESI高被引论文（PNAS论文与GRL论文），两篇论文获得2020年和2022年AGU Publications高影响力论文（下载排名前10%），一篇论文为EPSL期刊2024年高下载量论文。
报告摘要：
Premonitory slip and migrating foreshocks transitioning into an accelerating unstable rupture are commonly observed in experiments and less frequently in nature, but what controls their spatiotemporal evolution remains unclear. In this context, we conduct a series of displacement-driven triaxial compression experiments on porous sandstone samples containing a saw-cut fault under conditions of varying load point velocities (1 to 10 μm/s), confining pressures (35 to 75 MPa) and constant pore pressure (5 MPa). Integrating far-field mechanical and displacement measurements, near-fault strain gauge arrays, and a dense network of piezoelectric transducers, we find that local premonitory slip always occurs above a threshold stress, showing a crack-like propagating front with a slow speed up to 2 cm/s. Premonitory slip is accompanied by migrating small-magnitude precursory Acoustic Emissions (AEs) with dominantly shear-enhanced compaction source mechanisms transitioning to double-couple when approaching slip events. A transition from local premonitory slip to system-size slip event corresponds to the moment at which the premonitory slip front crosses the entire fault, followed by the emergence of system-size slip event with an accelerating rupture front in the opposite direction. Premonitory slip and precursory AEs display progressively accelerating processes, culminating in slow (< 5 µm/s slip rates) or fast (1 to 10 mm/s) slip events. With increasing load point velocities, average premonitory slip rates increase at reduced precursory time spans, leading to fast slip events. Increasing confining pressure causes increasing premonitory slip and off-fault precursory AEs, but has no much effect on premonitory slip rates. Precursory slip scales with co-seismic slip, and precursory slip process is predominately aseismic. Our results imply that local variations in loading conditions at slow slip and rupture velocities will affect spatiotemporal evolution of premonitory slip and associated foreshock activity。