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Seismic noise interferometry reveals transverse drainage configuration beneath the surging Bering Glacier

Zhan, Zhongwen (2019) Seismic noise interferometry reveals transverse drainage configuration beneath the surging Bering Glacier. Geophysical Research Letters, 46 (9). pp. 4747-4756. ISSN 0094-8276. https://resolver.caltech.edu/CaltechAUTHORS:20190426-100526470

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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.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1029/2019GL082411DOIArticle
ORCID:
AuthorORCID
Zhan, Zhongwen0000-0002-5586-2607
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.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Terrestrial Hazard Observation and Reporting CenterUNSPECIFIED
Issue or Number:9
Record Number:CaltechAUTHORS:20190426-100526470
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190426-100526470
Official Citation:Zhan, Z. ( 2019). Seismic noise interferometry reveals transverse drainage configuration beneath the surging Bering Glacier. Geophysical Research Letters, 46, 4747–4756. https://doi.org/10.1029/2019GL082411
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95019
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:26 Apr 2019 17:11
Last Modified:04 Dec 2019 18:31

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