From surface morphologies to inner structures: insights into hypermobility of the Nixu rock avalanche, southern Tibet, China
From surface morphologies to inner structures: insights into hypermobility of the Nixu rock avalanche, southern Tibet, China
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从表面形态到内部结构：对中国西藏南部尼须岩崩的超活动性的见解
DOI：
10.1007/s10346-020-01503-6
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发表时间：
2020-08
期刊：
影响因子：
6.7
通讯作者：
Liye Liao
中科院分区：
文献类型：
--
作者：
Qingli Zeng;Rongqiang Wei;Mauri McSaveney;Fengshan Ma;Guangxiang Yuan;Liye Liao
大型岩石雪崩通常会导致许多人死亡，并对远离源头的基础设施造成灾难性破坏。自瑞士Elm Slide的第一次研究以来，尚未就导致其超长运行的机制达成共识。目前对岩石崩落运动学和动力学的认识主要来自于对岩石表面形貌和内部结构的观察。在野外调查、高分辨率卫星影像解译和实验室筛选的基础上，对藏南尼须古地震崩落岩进行了分析。研究表明：（1）泥须岩崩可分解为三个侵位阶段，即由最初的深源岩崩转变为较大的次生岩屑崩，再加上相对较小的第三次岩屑崩。二次碎片雪崩的扩展促成了随后的长跳动传播。(2)在连续近端到远端暴露中观察到的形态特征（如陡坎、流带、横向脊、网格槽、丘和飞溅区）反映了碎片运动中应力-应变状态的变化，从拉伸到压缩，再到剪切和拉伸。(3)沿着河岸出露的复杂内部构造（如锯齿状构造、破碎碎屑、内部剪切带、连接断层、回旋纹层、滑脱、砂注入和侵入体）表明基底与岩石崩落碎屑之间存在薄基底剪切带和加压的挤压基底。(4)这表明湍流与推土在前面，但层流下的一个简单的剪切模型的主体。(5)分析表明，岩石崩塌的异常流动性涉及动量传递、基底夹带、液化基底剪切、内部剪切和岩石破碎的组合。
Large rock avalanches often result in many deaths and catastrophic damage to infrastructure far from source. No consensus has yet been reached on mechanisms causing their extraordinarily long runout since the first study at the Elm Slide, Switzerland. Much current understanding of rock avalanche kinematics and dynamics has been gained from observations of their surface morphologies and inner structures. Based on field surveys, high-resolution satellite image interpretation and laboratory sieving, we analyzed the ancient, earthquake-induced Nixu rock avalanche in southern Tibet, China, which has unique exposures of both morphological features and inner structures of the deposits. The study revealed that: (1) The Nixu rock avalanche probably could be disintegrated into three emplacement stages, transforming from an initial deep-seated rockslide into a large secondary debris avalanche, plus a relatively small third debris avalanche. The spreading of the secondary debris avalanche contributed to the subsequent long-runout propagation. (2) The morphological features observed in successive proximal to distal exposures (such as scarps, flowbands, transverse ridges, grid grooves, hummocks and splash zones) reflect the change in stress-strain state of debris in motion from tension, to compression, to shear and tension. (3) The complicated inner structures exposed along river banks (such as jigsaw structures, fragmented clasts, inner shear zones, conjunction faults, convoluted lamination, decollements, sand injections and intrusions), indicate the existence of a thin basal shear zone and a pressurized entrained-substrate between the substrate and rock avalanche debris. (4) This suggests turbulent flow with bulldozing in the front, but a laminar flow under a simple shear model for the main body. (5) The analysis suggests that the rock avalanche’s extraordinary mobility involves a combination of momentum transfer, substrate entrainment, liquefied basal shearing, internal shearing and rock fragmentation.
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DOI：
10.1098/rspa.1954.0186
发表时间：
1954-01-01
影响因子：
--
作者：
BAGNOLD, RA
通讯作者：
BAGNOLD, RA
藏南尼须岩崩的时代、地震成因及其对尼木活动断裂的意义
影响因子：
7.4
作者：
Qingli Zeng;Rongqiang Wei;Hua Du;Fengshan Ma;Guangxiang Yuan;Mauri McSaveney;Liye Liao
通讯作者：
Liye Liao
影响因子：
--
作者：
MELOSH, HJ
通讯作者：
MELOSH, HJ
影响因子：
5.3
作者：
R. M. Iverson;D. George;K. Allstadt;M. Reid;B. Collins;J. Vallance;S. Schilling;J. Godt;C. Cannon;C. Magirl;R. Baum;J. Coe;W. Schulz;J. Bower
通讯作者：
R. M. Iverson;D. George;K. Allstadt;M. Reid;B. Collins;J. Vallance;S. Schilling;J. Godt;C. Cannon;C. Magirl;R. Baum;J. Coe;W. Schulz;J. Bower
DOI：
10.1017/cbo9780511740367.006
发表时间：
2012-08
期刊：
--
影响因子：
--
作者：
T. Davies;M. McSaveney
通讯作者：
T. Davies;M. McSaveney