Englacial water transport is an integral part of the glacial hydrologic system, yet the geometry of englacial structures remains largely unknown. In this study, we explore the excitation of fluid resonance by small amplitude waves as a probe of englacial geometry. We model a hydraulic network consisting of one or more tabular cracks that intersect a cylindrical conduit, subject to oscillatory wave motion initiated at the water surface. Resulting resonant frequencies and quality factors are diagnostic of fluid properties and geometry of the englacial system. For a single crack–conduit system, the fundamental mode involves gravity-driven fluid sloshing between the conduit and the crack, at frequencies between 0.02 and 10 Hz for typical glacial parameters. Higher frequency modes include dispersive Krauklis waves generated within the crack and tube waves in the conduit. But we find that crack lengths are often well constrained by fundamental mode frequency and damping rate alone for settings that include alpine glaciers and ice sheets. Branching crack geometry and dip, ice thickness and source excitation function help define limits of crack detectability for this mode. In general, we suggest that identification of eigenmodes associated with wave motion in time series data may provide a pathway toward inferring englacial hydrologic structures.

中文翻译：

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弹性壁冰川传输网络中的流体共振

冰河水运是冰河水文系统的一个组成部分，但冰河结构的几何形状仍然很大程度上未知。在这项研究中，我们探索了小振幅波对流体共振的激发，作为对冰期几何的探测。我们模拟了一个由一个或多个板状裂缝组成的水力网络，这些裂缝与圆柱形管道相交，受到在水面上引发的振荡波动的影响。产生的共振频率和品质因数可用于诊断冰河系统的流体特性和几何形状。对于单个裂缝-管道系统，基本模式涉及重力驱动的流体在管道和裂缝之间晃动，典型冰川参数的频率在 0.02 到 10 Hz 之间。更高频率的模式包括在裂缝中产生的色散克劳克利斯波和管道中的管波。但我们发现，对于包括高山冰川和冰盖的环境，裂纹长度通常受到基模频率和阻尼率的良好限制。分支裂纹几何形状和倾角、冰层厚度和源激发函数有助于定义此模式的裂纹可检测性限制。一般来说，我们建议在时间序列数据中识别与波浪运动相关的特征模态可能会为推断冰期水文结构提供途径。冰厚度和源激发函数有助于定义此模式的裂纹可检测性限制。一般来说，我们建议在时间序列数据中识别与波浪运动相关的特征模态可能会为推断冰期水文结构提供途径。冰厚度和源激发函数有助于定义此模式的裂纹可检测性限制。一般来说，我们建议在时间序列数据中识别与波浪运动相关的特征模态可能会为推断冰期水文结构提供途径。