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.

鉴于技术进步，地震学家/冰川学家正在获得越来越大、越来越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，特别是识别更奇特的信号，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；冰震是否类似于地震）。 2004-2007 年四个夏季期间瑞士戈尔纳冰川观测到的约 250,000 次“冰震”就证明了这一点。 这项工作将提供对双材料表面失效和滑移引起的应力松弛模式范围的更广泛理解，这与从小高山冰川到主要板块边界断层的自然系统相关。完整的 Gorner Glacier 数据集容量约为 1 TB，其中仅约 10% 已被探索。 我们建议利用剩余的约 90% 的数据来：（1）根据 GPS 和经纬仪测量推断，确定冰震行为（时间/空间和波形频率内容）与冰川系统​​内应变之间的相关性和因果关系； (2)寻找类似震颤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可以逐季重复，评估冰川/基岩界面上的滑动与构造断层（即地震）推断的相似程度，以及如何有效监测冰川与地震技术。前所未有的数据量、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该项目成为一个潜在的变革性研究项目。