Summary of Research and Goals

Here's a summary of what I plan to work (and have been working) on this summer, along with some explanation of why it's important.  I'll give everyone an update on my progress soon.

 Ice Seismicity and Response to Environmental Stimuli at Yahtse Glacier

Given the apparent sensitivity of iceberg calving rates to climate change and the substantial contribution to overall glacier mass loss that it contributes, an advanced understanding of the mechanisms that control calving is a necessary precursor to making accurate predictions of future sea level rise in response to changes in global temperature.  Most current models relating calving rates to environmental stimuli are based primarily on empirical evidence and few have had their predictions extensively tested.
In order to further our understanding of glacier terminus dynamics, my project will incorporate observations from passive seismometers, time lapse cameras, a weather station, and a detailed observer log, seeking to identify pervasive relationships between the different records.  Hopefully, these relationships will reveal new details of mechanical failure within the glacier such that the impact of environmental stimuli on glacier mass loss can be better assessed.  
Although the vast majority of earth terrestrial ice exists as massive ice sheets in polar regions of Greenland and Antarctica, recent observations of their rapid response to environmental change suggest that many of the physical principles governing ice sheet flow may be thoroughly analogous to those of tidewater glaciers in non-polar regions.  Yahtse glacier, which feeds into central Alaska's Icy Bay from the Wrangell-St. Elias Mountains, is a particularly interesting example because it is currently undergoing an anomalous combination of change, thinning extensively (mass loss) at the same time that its terminus advances (apparent mass gain) down the glacier fjord.

A selection of targets for my summer research are as follows:

• Improve upon the characterization of glacier seismicity such that it can be distinguished from other seismic events without visual observation. Are there unique spectral characteristics apparent in calving seismicity?  Over what range of amplitudes can calving be detected?
• Develop methods for associating seismicity with motion of the ice mélange (debris in the fjord) that occurs subsequent to large calving events; does the presence of an ice mélange have an observable effect at the onset or in the coda of a waveform?
• Characterize the seismicity of different types of calving events (sub-aerial and sub-marine as a priority) such that they may be distinguished in seismic records.  Since sub-marine calving events seem to occur slower than sub-aerial events and release more ice, the event duration may be a telling factor in their characterization.
• Improve our understanding of how Yahtse Glacier discharges ice into the sea; what portion of the total discharge is accounted for by specific types of events?
• Observe patterns in calving activity at Yahtse Glacier potentially resulting from night and day temperature differences and tide change.
• Execute and improve upon an algorithm for automatically detecting, isolating, and partitioning calving events in seismic records.
• Locate the sources of large-scale glacier seismicity that cannot be correlated with visual observation at the terminus.

Although this is obviously more than I'll accomplish in one summer, it should serve as a guide
to keep me on track.  That being said, I have plenty of flexibility to explore the data in any direction
that appears most rich.