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

EAGER：通过研究高山冰川上的冰震来扩大我们对地震源的了解

• 批准号: 1239277
• 负责人: Deborah Kilb
• 金额: $ 10万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1239277&HistoricalAwards=false
• 关键词: EAGER; Expanding; Our; Understanding; Seismic

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.

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，特别是识别更奇异的信号，可能会回答有关冰川物理学的关键问题（例如，冰川如何与基岩耦合;冰震与地震相似吗）。2004年至2007年四个夏季期间在瑞士戈尔纳冰川记录的约250，000次“冰震”的观测就是例证。 这项工作将提供一个更广泛的理解范围内的应力松弛模式的故障和滑动的双材料表面，这是有关的自然系统，从小型高山冰川主要板块边界故障。完整的Gorner Glacier数据集的容量约为1 TB，其中只有约10%已被探索。 我们建议利用剩下的~90%的数据：（1）确定相关性，从而冰震的行为（时间/空间和波形频率内容）和冰川系统内的应变之间的因果关系，从GPS和经纬仪测量推断;和（2）寻找震颤样信号，并研究它们的来源。这些努力将使我们能够确定数据中的哪些方面是可重复的季节，以评估冰川/基岩界面上的滑动与构造断层上推断的滑动相似的程度（即，地震），以及如何有效地监测冰川与地震技术。这一前所未有的数据量的顶峰，工作的跨学科方面（地震学和冰川学），以及新颖的检测方法，使这成为一个潜在的变革性研究项目。