Seismic noise interferometry reveals transverse drainage configuration beneath the surging Bering Glacier
- Creators
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Zhan, Zhongwen
Abstract
Subglacial drainage systems are known to critically control ice flows, but their spatial configuration and temporal evolution are poorly constrained due to inaccessibility. Here we report a 12‐year‐long monitoring of the drainage underneath Bering Glacier, Alaska, by correlating ambient noise recorded at two seismic stations on the sides of the glacier. We find that the seismic surface waves traveling across Bering Glacier slowed down by 1–2% during its latest 2008–2011 surge, likely due to the switch of the subglacial drainage from a channelized system to a distributed system. In contrast to current models, the relative amplitude of velocity reductions for Rayleigh and Love waves requires the distributed drainage to be highly anisotropic and aligned perpendicular to the ice flow direction. We infer that the subglacial water flow is mainly through a network of transverse basal crevasses during surges and thus can sustain the high water pressure and ice flow speed.
Additional Information
© 2019 American Geophysical Union. Received 8 FEB 2019; Accepted 18 APR 2019; Accepted article online 25 APR 2019; Published online 3 MAY 2019. I am thankful for the Paul Silver enhancement award from IGPP, UC San Diego, which helped start this project, and the Terrestrial Hazard Observation and Reporting (THOR) fund at Caltech for supporting the project. This work benefitted from discussions with Timothy Bartholomaus, Victor Tsai, Rick Aster, and Fabian Walter and comments from Florent Gimbert and an anonymous reviewer. The seismic data used in this study are from the Alaska Regional Network (https://doi.org/10.7914/SN/AK), downloaded through the Incorporated Research Institutions for Seismology (IRIS). I thank Voon‐Hui Lai for helping set up the 3‐D finite‐difference simulations. The satellite image of Bering Glacier in Figure 1a is from the Landsat 7 Science Team.Attached Files
Published - Zhan-2019-Geophysical_Research_Letters.pdf
Supplemental Material - grl58917-sup-0001-2019gl082411-s01.pdf
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Additional details
- Eprint ID
- 95019
- Resolver ID
- CaltechAUTHORS:20190426-100526470
- Terrestrial Hazard Observation and Reporting Center
- Created
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2019-04-26Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory, Division of Geological and Planetary Sciences