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Seismic Noise Interferometry Reveals Transverse Drainage Configuration Beneath the Surging Bering Glacier
Author(s) -
Zhan Zhongwen
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl082411
Subject(s) - geology , glacier , channelized , geomorphology , drainage , ice stream , surge , transverse plane , amplitude , seismology , oceanography , cryosphere , sea ice , ecology , telecommunications , physics , structural engineering , quantum mechanics , computer science , engineering , biology
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.