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Integrated electrical resistivity tomography (ERT) and self-potential (SP) techniques for assessing hydrological processes within glacial lake moraine dams

Citation

Thompson, S and Kulessa, B and Luckman, A, Integrated electrical resistivity tomography (ERT) and self-potential (SP) techniques for assessing hydrological processes within glacial lake moraine dams, Journal of Glaciology, 58, (211) pp. 849-858. ISSN 0022-1430 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 International Glaciological Society

DOI: doi:10.3189/2012JoG11J235

Abstract

Moraine dams can be inherently unstable, but effective assessment strategies remain poorly identified. We integrate electrical resistivity tomography (ERT) with electrical self-potential (SP) and lake-level measurements to investigate the structure of, and hydrological processes within, a moraine-dam complex adjacent to Miage glacier, Italy. This complex separates two meltwater lakes characterized by an efficient subterranean hydraulic connection. Our ERT data reveal a continuous free surface within the complex, whose morphology reflects the topography of the moraine complex akin to unconfined groundwater aquifers. SP data were corrected for spatial changes in the thickness of the upper unsaturated layer using principles of electrography. The residual streaming-potential map is consistent with Darcian flow of lake waters through the moraine complex, characterized by a negative-to-positive potential change from <-30 mV to >+70 mV. These electrical signatures are consistent with those generated by water seepage through earth dams in various non-glacial settings. Integrated electrical geophysical methods thus provided an inexpensive and unobtrusive evaluation of the hydrological properties of and processes within the moraine complex. Since spatio-temporal patterns of subsurface water flow critically affect the strengths of moraine sediments, such methods promise to be powerful in assessing the long-term stability of moraine-dammed glacial lakes.

Item Details

Item Type:Refereed Article
Keywords:glacial moraine, electrical resistivity, self-potential, glacial lake
Research Division:Earth Sciences
Research Group:Geophysics
Research Field:Electrical and electromagnetic methods in geophysics
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Natural hazards
Objective Field:Natural hazards not elsewhere classified
UTAS Author:Thompson, S (Dr Sarah Thompson)
ID Code:140809
Year Published:2012
Web of Science® Times Cited:21
Deposited By:Australian Antarctic Program Partnership
Deposited On:2020-09-09
Last Modified:2020-10-19
Downloads:0

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