Seismic and geodetic signatures of fault slip at the Slumgullion Landslide Natural Laboratory
Seismic and geodetic signatures of fault slip at the Slumgullion Landslide Natural Laboratory
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DOI：
10.1029/2011jb008304
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发表时间：
2011-09
影响因子：
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通讯作者：
J. Gomberg;W. Schulz;P. Bodin;J. Kean
中科院分区：
文献类型：
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作者：
J. Gomberg;W. Schulz;P. Bodin;J. Kean
[1]我们测试的假设，斯卢姆古利昂滑坡是一个有用的天然实验室，观察断层滑动，特别是滑动沿着其基底表面和侧边界走滑断层发生的地震和地震模式相当丰富的沿着地壳和板块规模的边界。我们的研究提供了新的约束滑坡运动模型。我们监测滑坡变形与临时部署的29元素棱镜阵列的机器人经纬仪和88站地震网络，补充永久性引伸计和环境仪器。非地震变形观测表明，滑坡的大块以每天约厘米的速度稳定移动，可能会被几毫米的变化打断，而小于几十米的块体的局部瞬时滑动事件经常发生。我们记录了丰富多样的地震信号，几乎所有这些信号都起源于监测网络边界之外或来自侧边走滑断层。我们的地震网络下方的滑坡基面可能几乎完全地震滑动。我们的研究结果提供了独立的佐证以前的推论，即沿沿着部分的侧向边界走滑断层的抗滑加强控制整体滑坡运动，作为地震辐射制动器，限制加速度的抗震滑动基面。膨胀加强也被调用在最近的模型中的瞬态滑动和震颤源沿着地壳和板块规模的故障表明，滑坡可能确实是一个有用的天然实验室，用于测试预测的具体机制，控制在所有规模的断层滑动。
[1] We tested the hypothesis that the Slumgullion landslide is a useful natural laboratory for observing fault slip, specifically that slip along its basal surface and side-bounding strike-slip faults occurs with comparable richness of aseismic and seismic modes as along crustal- and plate-scale boundaries. Our study provides new constraints on models governing landslide motion. We monitored landslide deformation with temporary deployments of a 29-element prism array surveyed by a robotic theodolite and an 88-station seismic network that complemented permanent extensometers and environmental instrumentation. Aseismic deformation observations show that large blocks of the landslide move steadily at approximately centimeters per day, possibly punctuated by variations of a few millimeters, while localized transient slip episodes of blocks less than a few tens of meters across occur frequently. We recorded a rich variety of seismic signals, nearly all of which originated outside the monitoring network boundaries or from the side-bounding strike-slip faults. The landslide basal surface beneath our seismic network likely slipped almost completely aseismically. Our results provide independent corroboration of previous inferences that dilatant strengthening along sections of the side-bounding strike-slip faults controls the overall landslide motion, acting as seismically radiating brakes that limit acceleration of the aseismically slipping basal surface. Dilatant strengthening has also been invoked in recent models of transient slip and tremor sources along crustal- and plate-scale faults suggesting that the landslide may indeed be a useful natural laboratory for testing predictions of specific mechanisms that control fault slip at all scales.