Flank instability assessment at Kick-'em-Jenny submarine volcano (Grenada, Lesser Antilles): a multidisciplinary approach using experiments and modeling
Flank instability assessment at Kick-'em-Jenny submarine volcano (Grenada, Lesser Antilles): a multidisciplinary approach using experiments and modeling
复制标题
DOI：
10.1007/s00445-016-1090-8
复制
发表时间：
2017-01-01
影响因子：
3.5
通讯作者：
Carey, S.
中科院分区：
文献类型：
--
作者：
Dondin, F. J-Y.;Heap, M. J.;Carey, S.
Kick-'em-Jenny（KeJ）-位于CA。格林纳达岛以北8公里处，是小安的列斯群岛火山弧中唯一的活海底火山。先前对KeJ的调查显示，它位于从过去的侧翼不稳定事件继承的塌陷疤痕内。为了评估未来崩溃的可能性，我们在这里采用了实验室和建模相结合的方法。使用遥控潜水器（REACH）收集的熔岩提供了样本，以进行KeJ建筑物材料的第一次岩石物理性质测量。单轴和三轴变形试验表明，围岩的主要破坏模式是脆性破坏。因此，扩张性断裂（如香槟喷口处的断裂）将有助于附近充满岩浆的管道的放气，有利于喷出行为。这些实验室数据，然后被用来作为输入参数的边坡稳定性模型。首先，相对边坡稳定性分析表明，西南到N部门的火山显示赤字的质量/体积相对于火山（理想的三维表面）。采用极限平衡法（LEM）进行的边坡稳定性分析表明，KeJ目前是稳定的，因为所有稳定系数或安全系数（Fs）的值都大于1。FS的最低值被发现的西南-西北部门的火山（该部门显示质量/体积赤字）。虽然目前稳定，但KeJ未来可能会变得不稳定。不稳定性（Fs的严重降低）可能是由于，例如，由于一个隐圆顶的增长而导致的超压。我们的模拟表明，不稳定性引起的侧翼崩溃将最有可能从西南偏西的部门KeJ开始，因此动员量至少约。0.7 km（3）。的动员。0.7 km（3）的物质肯定能够产生海啸，对西印度群岛南部岛屿构成重大危险。
Kick-'em-Jenny (KeJ)-located ca. 8 km north of the island of Grenada-is the only active submarine volcano of the Lesser Antilles Volcanic Arc. Previous investigations of KeJ revealed that it lies within a collapse scar inherited from a past flank instability episode. To assess the likelihood of future collapse, we employ here a combined laboratory and modeling approach. Lavas collected using a remotely operated vehicle (ROV) provided samples to perform the first rock physical property measurements for the materials comprising the KeJ edifice. Uniaxial and triaxial deformation experiments showed that the dominant failure mode within the edifice host rock is brittle. Edifice fractures (such as those at Champagne Vent) will therefore assist the outgassing of the nearby magma-filled conduit, favoring effusive behavior. These laboratory data were then used as input parameters in models of slope stability. First, relative slope stability analysis revealed that the SW to N sector of the volcano displays a deficit of mass/volume with respect to a volcanoid (ideal 3D surface). Slope stability analysis using a limit equilibrium method (LEM) showed that KeJ is currently stable, since all values of stability factor or factor of safety (Fs) are greater than unity. The lowest values of Fs were found for the SW-NW sector of the volcano (the sector displaying a mass/volume deficit). Although currently stable, KeJ may become unstable in the future. Instability (severe reductions in Fs) could result, for example, from overpressurization due to the growth of a cryptodome. Our modeling has shown that instabilityinduced flank collapse will most likely initiate from the SWNW sector of KeJ, therefore mobilizing a volume of at least ca. 0.7 km(3). The mobilization of ca. 0.7 km(3) of material is certainly capable of generating a tsunami that poses a significant hazard to the southern islands of the West Indies.