Insights into the emplacement dynamics of volcanic landslides from high-resolution 3D seismic data acquired offshore Montserrat, Lesser Antilles
Insights into the emplacement dynamics of volcanic landslides from high-resolution 3D seismic data acquired offshore Montserrat, Lesser Antilles
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DOI：
10.1016/j.margeo.2012.10.004
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发表时间：
2013
期刊：
影响因子：
2.9
通讯作者：
G. Crutchley;J. Karstens;C. Berndt;P. Talling;S. Watt;M. Vardy;V. Hühnerbach;M. Urlaub;S. Sarkar;D. Klaeschen;M. Paulatto;A. Friant;E. Lebas;F. Maeno
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文献类型：
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作者：
G. Crutchley;J. Karstens;C. Berndt;P. Talling;S. Watt;M. Vardy;V. Hühnerbach;M. Urlaub;S. Sarkar;D. Klaeschen;M. Paulatto;A. Friant;E. Lebas;F. Maeno
我们目前的结果，从第一个三维（3D）海洋地震数据集收集的火山滑坡沉积物，获得近海的苏弗里埃尔山火山蒙特塞拉特岛在小安的列斯群岛。3D数据使人们能够详细分析这些质量浪费型矿床内部和周围的各种特征，如表面变形组构、搬运块体的分布和大小、就位方向的变化和对海底地层的侵蚀。最近的碎片雪崩存款（存款1）的表面上保存的变形特征揭示了空间变化的减速的证据，因为质量故障来休息在海底。块分布表明，故障蔓延非常迅速，没有发展纵向脊的趋势。一个较老的火山侧翼塌陷存款（存款2）似乎与海底沉积物的大规模二次故障内在相关。我们观察到明显的侵蚀直接下坡的一个突出的端墙，在平移滑动的分层沉积物开始。深大断层控制了端墙的形状和位置，地层关系表明，滑动与火山侧翼塌陷侵位同时发生。我们还确定了存款1和存款2之间的一个非常不同的质量浪费单位，可能是作为一系列来自火山碎屑流的颗粒负载的质量流，很像最近（自1995年以来）的蒙特塞拉特近海沉积阶段，但在更大的规模。这项研究强调了三维地震数据在了解火山岛近海滑坡就位过程中的作用。
We present results from the first three-dimensional (3D) marine seismic dataset ever collected over volcanic landslide deposits, acquired offshore of the Soufrière Hills volcano on the island of Montserrat in the Lesser Antilles. The 3D data enable detailed analysis of various features in and around these mass wasting deposits, such as surface deformation fabrics, the distribution and size of transported blocks, change of emplacement direction and erosion into seafloor strata. Deformational features preserved on the surface of the most recent debris avalanche deposit (Deposit 1) reveal evidence for spatially-variant deceleration as the mass failure came to rest on the seafloor. Block distributions suggest that the failure spread out very rapidly, with no tendency to develop longitudinal ridges. An older volcanic flank collapse deposit (Deposit 2) appears to be intrinsically related to large-scale secondary failure of seafloor sediments. We observe pronounced erosion directly down-slope of a prominent headwall, where translational sliding of well-stratified sediments was initiated. Deep-reaching faults controlled the form and location of the headwall, and stratigraphic relationships suggest that sliding was concurrent with volcanic flank collapse emplacement. We also identified a very different mass wasting unit between Deposit 1 and Deposit 2 that was likely emplaced as a series of particle-laden mass flows derived from pyroclastic flows, much like the recent (since 1995) phase of deposition offshore Montserrat but at a much larger scale. This study highlights the power of 3D seismic data in understanding landslide emplacement processes offshore of volcanic islands.