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.
