Improving our understanding of glacial sliding is crucial for constraining basal drag in ice dynamics models. We use icequakes, sudden releases of seismic energy as the ice slides over the bed, to provide geophysical observations that can be used to aid understanding of the physics of glacial sliding and constrain ice dynamics models. These icequakes are located at the bed of an alpine glacier in Switzerland and the Rutford Ice Stream, West Antarctica, two extremes of glacial settings and spatial scales. We investigate a number of possible icequake source mechanisms by performing full waveform inversions to constrain the fundamental physics and stress release during an icequake stick‐slip event. Results show that double‐couple mechanisms best describe the source for the events from both glacial settings and the icequakes originate at or very near the ice‐bed interface. We also present an exploratory method for attempting to measure the till shear modulus, if indirect reflected icequake radiation is observed. The results of this study increase our understanding of how icequakes are associated with basal drag while also providing the foundation for a method of remotely measuring bed shear strength.

中文翻译：

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研究冰川滑动的冰源机制

改善我们对冰川滑动的理解对于限制冰动力学模型中的基础阻力至关重要。我们使用地震，即冰在床上滑动时地震能量的突然释放，来提供地球物理观测结果，以帮助理解冰川滑动的物理过程并限制冰动力学模型。这些冰震位于瑞士的高山冰川和南极西部的拉特福德冰河，这是两个极端的冰川环境和空间尺度。我们通过执行完整的波形反演来限制冰粘滑事件中的基本物理现象和应力释放，从而研究了多种可能的冰源机制。结果表明，双耦合机制最能描述来自冰川环境的事件的来源，而冰震始于或接近冰床界面。如果观察到间接反射的冰辐射，我们还提供了一种探索方法，用于尝试测量耕层剪切模量。这项研究的结果加深​​了我们对冰与基底阻力的关系的理解，同时也为远程测量河床抗剪强度的方法提供了基础。