Relating Glacier-Generated Seismicity to Ice Motion, Basal Processes and Iceberg Calving

被动地震方法构成了这项为期3年的多学科提案的核心，旨在调查冰川运动、基本过程和快速变化的潮水冰川上的冰山崩解之间的时间和空间关系。拟议的测量将把冰川产生的地震信号与物理冰川过程联系起来。目前，人们对冰川产生的波形知之甚少。了解它们的来源机制可以促进对地球-S冰冻圈动态物质平衡的认识，也可以改进冰川侵蚀和景观演化的模型和理解。一项为期一年的初步研究的初步结果突出表明，阿拉斯加冰湾的潮水冰川是冰川产生的地震能量的区域主导来源。冰湾是最佳的研究地点，因为它的冰川高度活跃，物流简单，与格陵兰正在分解的出口冰川有相似之处。初步研究结果表明，利用长期、高分辨率的运动、地震活动和冰川几何变化的记录，有可能开发出冰川侵蚀的定量指标。拟议的工作将记录具有密集台站间距的局部台网内的地震事件，并同时观测三维冰川位移和冰川几何变化。冰山崩解和基本过程的测量是具有挑战性的，应用现成的和高度发达的地震方法来解决这些问题具有重要的前景。该提案将支持三位具有多学科背景的早期职业科学家的合作。来自实验的数据将在UNAVCO、IRIS、NSIDC和阿拉斯加大学存档。

Passive seismic methods form the core of this 3-year, multi-disciplinary proposal designed to investigate temporal and spatial relationships between ice motion, basal processes and iceberg calving at a rapidly changing tidewater glacier. The proposed measurements will link glacier-generated seismic signatures to physical glaciological processes. At present, glacier generated waveforms are poorly understood. Understanding their source mechanisms could advance knowledge of the dynamic mass balance of Earth?s cryosphere, as well as improve models and understanding of glacier erosion and landscape evolution. Preliminary results from a 1-year pilot study highlight the tidewater glaciersof Icy Bay, Alaska as the regionally dominant source of glacier-generated seismic energy. Icy Bay is the optimal study site because of its highly dynamic glaciers, logistical simplicity and similarities with disintegrating outlet glaciers in Greenland. Pilot study results show potential to make use of long duration, high-resolution records of motion, seismicity and changes in geometry in concert to develop quantitative proxies for glacier erosion.The proposed work will record seismic events within a local network with densestation spacing, and simultaneously observe 3-D ice displacement and glacier geometry changes. Iceberg calving and basal processes are challenging to measure, and applying readily available and highly developed seismic methods to these problems holds significant promise. The proposal will support the collaboration of three early-career scientists with multi-disciplinary backgrounds. Data from the experiments will be archived at UNAVCO, IRIS, NSIDC and at the University of Alaska.and iceberg calving flux