Evaluating Topographic Effects on Ground Deformation: Insights from Finite Element Modeling
Evaluating Topographic Effects on Ground Deformation: Insights from Finite Element Modeling
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DOI：
10.1007/s10712-015-9325-3
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发表时间：
2015-04
影响因子：
4.6
通讯作者：
E. Ronchin;A. Geyer;J. Martí
中科院分区：
文献类型：
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作者：
E. Ronchin;A. Geyer;J. Martí
地面变形已被证明是火山不稳定最常见的信号之一。虽然火山通常与显著的地形起伏联系在一起，但大多数分析模型都假定地球表面是平坦的。然而，已经证实，这种近似可能导致对记录的地表变形数据的重要误解。在这里，我们对地形如何影响嵌入弹性均匀介质中的球形压力源产生的地面变形信号，以及这些变化如何与表征地形形式的不同地形参数（例如，坡度、坡向、曲率）相关联进行了系统和定量的分析。为此，我们汇集了以前发表的论文的结果，并补充了新的轴对称和三维有限元（FE）模型结果。首先，我们以参数化的方式研究了以压力源轴为中心的火山大厦的影响。其次，我们建立了新的三维有限元模型，模拟了三个不同的火山区的真实地形，代表了火山区常见的地形情景：拉包尔火山口（巴布亚新几内亚）和特内里费火山岛和耶罗火山岛（加那利群岛）。然后将计算出的差异与一系列地形参数相关联。最终目的是调查由于不同的地形特征（例如，崩塌的火山口结构，突出的中央大厦，大型滑坡疤痕），在火山地区使用半空间模型可能产生的人工产物。
Ground deformation has been demonstrated to be one of the most common signals of volcanic unrest. Although volcanoes are commonly associated with significant topographic relief, most analytical models assume the Earth’s surface as flat. However, it has been confirmed that this approximation can lead to important misinterpretations of the recorded surface deformation data. Here we perform a systematic and quantitative analysis of how topography may influence ground deformation signals generated by a spherical pressure source embedded in an elastic homogeneous media and how these variations correlate with the different topographic parameters characterizing the terrain form (e.g., slope, aspect, curvature). For this, we bring together the results presented in previous published papers and complement them with new axisymmetric and 3D finite element (FE) model results. First, we study, in a parametric way, the influence of a volcanic edifice centered above the pressure source axis. Second, we carry out new 3D FE models simulating the real topography of three different volcanic areas representative of topographic scenarios common in volcanic regions: Rabaul caldera (Papua New Guinea) and the volcanic islands of Tenerife and El Hierro (Canary Islands). The calculated differences are then correlated with a series of topographic parameters. The final aim is to investigate the artifacts that might arise from the use of half-space models at volcanic areas due to diverse topographic features (e.g., collapse caldera structures, prominent central edifices, large landslide scars).