Improving estimates of future sea level rise will require an improved understanding of the basal ice dynamics of the ice sheets. Because the presence of liquid water greatly affects the dynamics of these bodies of ice, a passive seismic method for determining the spatial and temporal distribution of liquid water within ice bodies is highly desirable. With these goals in mind, we investigate the role of fluid filled fractures in creating seismicity observed in glaciers and ice sheets. We model the resonant modes of a hydraulic fracture, and demonstrate how this model can be used to estimate the length and aperture of hydraulic fractures from passive seismic data.
Earthquakes in Ice: Using Seismology to Study the Dynamics of Glaciers and Ice Sheets
The fate of the West Antarctic Ice Sheet is the most uncertain part of global sea level rise projections. The dynamics of fast flowing ice in this region are both scientifically fascinating and important for understanding future sea level rise. Seismic data similar to those used to understand tectonic earthquakes may provide new insights into these dynamics. Several projects are possible. (1) Seismographs recorded on the ice in Antarctica may be used to understand the physics at the bed of the ice sheet. In this project, small repeating earthquakes that occur during large-scale sliding will be used to estimate the coefficient of friction at the ice-rock interface. (2) Migrating waves of tidally modulated micro seismicity in Antarctica have been observed but the source of these events is not clear. A recently developed model of a resonating water-filled fracture will be used to analyze such microseismic catalogs to determine if they are due to the movement of fluid at the ice sheet bed. For both projects, prior programming experience in MATLAB or a high-level programming language will be essential, and introductory mechanics is recommended.
Seismic waves from the cryosphere transmit information from otherwise difficult to observe systems to distant seismometers. Despite the importance of understanding mass fluxes, cryospheric stability, and integrated climate feedbacks, the constraints offered by seismicity remain poorly incorporated in our general understanding of these topics. We invite presentations that draw on seismic analyses to better understand the dynamics and behavior of the cryosphere. We welcome theoretical, observational, and experimental results pertaining to seismic observations. Topics of interest include but are not limited to basal sliding, iceberg calving, fluid transients, tidally modulated seismicity, analysis of sea ice cover, crevassing, and seismicity within icebergs.
(650) 498 5606
397 Panama Mall
Stanford, CA 94305