Abstract The goal of this study is to explore “ideal” analytic functional forms that best fit the topographic shape of N = 190 isolated stratovolcanoes from around the world. Using a stochastic model for the piling of lava flows to demonstrate one set of physical processes that give rise to a stratovolcano's topography, we find that although the ideal form fits well for many stratovolcanoes, there exist deviations from this shape—particularly where the edifice is more protuberant than expected. We explore sub-surface factors—such as the emplacement of magma beneath a volcano edifice—that may be responsible for these deviations and estimate the relative contribution of dyke intrusions on the height and shape of a volcanic edifice versus the constructional piling of lava. From this comparison, we are able to gain more insight into the role of important subsurface physical factors, such as chamber depth and total intruded volume. We find that low basal ellipticity is a characteristic of nearly all volcanoes that fit the ideal stratovolcano form. By fitting along each quadrant bisected by either a semi-major or semi-minor ellipse axis, we find that the volcanoes chosen in this study fall into four groups: (1) volcanoes that are axisymmetric and fit the ideal form well, (2) volcanoes that are not axisymmetric but may be fit to the ideal form using different fitting parameters in each quadrant, (3) volcanoes that have axisymmetric protuberant deviations in all quadrants, and (4) volcanoes that have non-axisymmetric protuberant deviations that are only present in a couple of quadrants. We show that, in some cases, the non-axisymmetry of volcanoes in category (2) may be understood as the result of the piling of eruptive products along a regional planar trend. For edifices in categories (3) and (4), we model protuberant deviations as the result of a statistical distribution of elastic tensile dislocations representing dykes, which emanate from a magma reservoir and cause uplift at the surface. We support this interpretation of the “excess” topography in a few case studies where independent geologic and geophysical data corroborate our model results.

中文翻译：

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层状火山地形形态分析

摘要 本研究的目标是探索最适合来自世界各地的 N = 190 个孤立层状火山的地形形状的“理想”解析函数形式。使用熔岩流堆积的随机模型来展示产生层状火山地形的一组物理过程，我们发现虽然理想的形式非常适合许多层状火山，但与这种形状存在偏差 - 特别是在建筑物所在的位置比预期的更突出。我们探索了可能导致这些偏差的地下因素——例如火山建筑物下方的岩浆侵位——并估计了岩墙侵入对火山建筑物的高度和形状与熔岩结构堆积的相对贡献。从这个比较来看，我们能够更深入地了解重要的地下物理因素的作用，例如腔室深度和总侵入量。我们发现，低基底椭圆度是几乎所有符合理想层状火山形式的火山的特征。通过沿着被半长椭圆轴或半短椭圆轴平分的每个象限拟合，我们发现本研究中选择的火山分为四组：（1）轴对称且非常适合理想形状的火山，（2）非轴对称但可以在每个象限中使用不同拟合参数拟合到理想形式的火山，(3) 在所有象限中具有轴对称突起偏差的火山，以及 (4) 具有仅存在的非轴对称突起偏差的火山在几个象限中。我们表明，在某些情况下，类别（2）中火山的非轴对称性可以理解为沿区域平面趋势堆积的喷发产物的结果。对于类别 (3) 和 (4) 中的建筑物，我们将突出偏差建模为代表岩脉的弹性拉伸位错的统计分布的结果，岩脉源自岩浆储层并导致地表隆起。在一些案例研究中，我们支持对“过量”地形的这种解释，其中独立的地质和地球物理数据证实了我们的模型结果。来自岩浆库并导致地表隆起。在一些案例研究中，我们支持对“过量”地形的这种解释，其中独立的地质和地球物理数据证实了我们的模型结果。来自岩浆库并导致地表隆起。在一些案例研究中，我们支持对“过量”地形的这种解释，其中独立的地质和地球物理数据证实了我们的模型结果。