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Estimating and managing blowout risk during access to subglacial Antarctic lakes

Brito, Mario P.; Griffiths, Gwyn; Mowlem, Matthew; Makinson, Keith. 2013 Estimating and managing blowout risk during access to subglacial Antarctic lakes. Antarctic Science, 25 (1). 107-118. 10.1017/S0954102012000442

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Abstract/Summary

As Antarctic subglacial lake research progresses to in situ exploration an important topic is the lake’s probable gas concentration. Depending on hydrological setting, subglacial lakes may contain large amounts of dissolved gas or gas trapped within clathrates. Consequently, access can be potentially dangerous due to the risk of blowout where depressurization could lead to high-speed ejection of water and gas from a borehole. We present a structured approach to assess the blowout risk in subglacial lake exploration. The approach integrates a generic event tree, applicable to open and closed hydrological systems, with site-specific expert judgment incorporating rigorous probabilistic formulations. The methodology is applied to a motivating example: Ellsworth Subglacial Lake. Judgments elicited through a formal process were provided by five experts with 88 years combined experience that, after aggregation, gave a median risk of blowout of 1 in 2186 with a lower quartile of 1 in 3433 and an upper quartile of 1 in 1341. This approach can be applied to any subglacial lake given a modicum of knowledge on its hydrological setting, as uncertainty can be captured through the elicited judgments. Additionally, the event tree analysis informs blowout mitigation strategies to reduce risk of injury or death.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1017/S0954102012000442
Programmes: BAS Programmes > Polar Science for Planet Earth (2009 - ) > Polar Oceans
ISSN: 0954-1020
Additional Information. Not used in RCUK Gateway to Research.: Copyright 2012 Antarctic Science Ltd
Additional Keywords: Ellsworth Subglacial Lake, expert judgment, hot-water drilling
Date made live: 27 Feb 2013 09:35 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/500156

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