Scholarlink

<p>Acoustic emission (AE) events during frictional sliding on laboratory fault gouge are closely linked to microphysical processes, including grain comminution, force chain collapse, and strain localization. Such micro-seismic events in the lab may also provide important constraints on foreshock characteristics and rupture nucleation in nature. Here, we locate AE events with millimeter accuracy and compare their spatiotemporal evolution during stick–slip in soda-lime glass and stable sliding in quartz sand gouge. The gouges are sandwiched between corrugated PMMA blocks and loaded to failure under constant shear velocity and constant normal displacement boundary conditions. We observe abrupt broadening of the AE activity perpendicular to the slip plane shortly before stick–slip, i.e., after 95% of the interseismic period, coinciding with rapid slip acceleration. Conversely, stable sliding lacks final-stage slip acceleration and the AE activity width shows only minor variations, which are correlated with gradual fault compaction and dilation. These differences in fault dilation and AE activity width may suggest different micromechanical processes associated with stable sliding vs. stick–slip (e.g., grain rotation and translation vs. force chain formation and collapse). We compare the tests on planar PMMA-gouge with experiments on rough, granite faults with off-fault damage. The latter exhibit pronounced AE localization before stick slip which starts early in the interseismic period. The width of AE activity zones on rough faults is reduced by a factor of ~ 2.5 (i.e., 10&#xa0;mm to 4&#xa0;mm) before dynamic failure compared to a factor of ~ 2 in planar soda lime glass (i.e., from 2 to 1&#xa0;mm). Collectively, these findings demonstrate that microseismicity localization before labquakes, and potentially earthquakes, is strongly influenced by granular dynamics, gouge composition, and off-fault damage. Documenting these factors is crucial for an improved understanding of fault mechanics and earthquake nucleation.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Differences in Spatial Localization of Acoustic Emissions During Stick–Slip and Stable Sliding on Laboratory Fault Gouge

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年6月19日

查看全文
  • Roshan Koirala,
  • Navin Thapa,
  • Thomas Goebel

摘要

Acoustic emission (AE) events during frictional sliding on laboratory fault gouge are closely linked to microphysical processes, including grain comminution, force chain collapse, and strain localization. Such micro-seismic events in the lab may also provide important constraints on foreshock characteristics and rupture nucleation in nature. Here, we locate AE events with millimeter accuracy and compare their spatiotemporal evolution during stick–slip in soda-lime glass and stable sliding in quartz sand gouge. The gouges are sandwiched between corrugated PMMA blocks and loaded to failure under constant shear velocity and constant normal displacement boundary conditions. We observe abrupt broadening of the AE activity perpendicular to the slip plane shortly before stick–slip, i.e., after 95% of the interseismic period, coinciding with rapid slip acceleration. Conversely, stable sliding lacks final-stage slip acceleration and the AE activity width shows only minor variations, which are correlated with gradual fault compaction and dilation. These differences in fault dilation and AE activity width may suggest different micromechanical processes associated with stable sliding vs. stick–slip (e.g., grain rotation and translation vs. force chain formation and collapse). We compare the tests on planar PMMA-gouge with experiments on rough, granite faults with off-fault damage. The latter exhibit pronounced AE localization before stick slip which starts early in the interseismic period. The width of AE activity zones on rough faults is reduced by a factor of ~ 2.5 (i.e., 10 mm to 4 mm) before dynamic failure compared to a factor of ~ 2 in planar soda lime glass (i.e., from 2 to 1 mm). Collectively, these findings demonstrate that microseismicity localization before labquakes, and potentially earthquakes, is strongly influenced by granular dynamics, gouge composition, and off-fault damage. Documenting these factors is crucial for an improved understanding of fault mechanics and earthquake nucleation.