EAGER: Expanding Our Understanding of Seismic Sources via Investigations of Icequakes on an Alpine Glacier

随着技术的进步，地震学家/冰川学家正在获得越来越大和更高质量的连续和半连续地震波形流的数据集。这些数据无疑包含重要但不容易识别的信号，需要额外的用户交互才能正确识别。仔细提取这些数据，特别是为了识别更奇异的信号，可能会回答有关冰川物理的关键问题(例如，冰川如何与基岩耦合；冰川与地震相似)。在瑞士戈尔纳冰川2004-2007年的四个夏季期间，观测到了大约25万只“冰猴”，这就是例证。这项工作将使人们更广泛地了解在滑动的双材料表面上的破坏和滑动引起的应力松弛模式的范围，这与从小的高山冰川到主要的板块边界断层的自然系统有关。整个戈尔纳冰川数据集的体积约为1TB，其中只有10%的数据被勘探过。我们建议利用剩余的90%的数据来：(1)确定冰川行为(时间/空间和波形频率含量)与从GPS和经纬仪测量得出的冰川系统内的应变之间的相关性和因果联系；以及(2)搜索类似地震的信号并研究其来源。这些努力将使我们能够确定数据中的哪些方面是季节可重复的，评估冰川/基岩界面滑动与构造断层(即地震)推断的相似程度，以及如何利用地震技术有效地监测冰川。史无前例的数据量达到顶峰，这项工作的跨学科方面(地震学和冰川学)，以及新的探测方法使这项研究成为一个潜在的变革性研究项目。

Given technological advances, seismologists/glaciologists are obtaining ever-increasingly larger and higher quality datasets of continuous and semi-continuous seismic waveform streams. These data undoubtedly contain important, but not readily recognized, signals that require additional user-interaction to properly identify. Carefully distilling these data, particularly to identify the more exotic signals, could potentially answer key questions about the physics of glaciers (e.g., how does a glacier couple to the bedrock; are icequakes similar to earthquakes). This is exemplified by observations of ~250,000 "icequakes" recorded during the four summer seasons 2004-2007 on the Gorner Glacier in Switzerland. This work will provide a broader understanding of the range of modes of stress relaxation by failure and slip across sliding bi-material surfaces, which is relevant to natural systems ranging from small alpine glaciers to major plate-boundary faults. The complete Gorner Glacier dataset has a volume of ~1 terabyte of which only ~10% has been explored. We propose to exploit the remaining ~90% of data to: (1) identify correlations and thus causal connections between the behavior of icequakes (temporal/spatial and waveform frequency content) and strain within the glacier system as inferred from GPS and theodolite measurements; and (2) search for tremor-like signals and study their sources. These efforts will allow us to identify what aspects in the data are repeatable season to season, to assess the extent to which slip on glacial/bedrock interfaces is analogous to that inferred on tectonic faults (i.e., earthquakes), and how to efficiently monitor glaciers with seismic techniques. The culmination of this unprecedented amount of data, the interdisciplinary aspect of the work (seismology and glaciology), and the novel detection methods make this a potentially transformative research project.