Towards improved ground models for slope instability evaluations through better characterization of sediment-hosted gas-hydrates |
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| Authors: | D A Gunn L M Nelder C A Rochelle K Bateman P D Jackson M A Lovell P R N Hobbs D Long J G Rees P Schultheiss J Roberts T Francis |
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| Institution: | British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG, UK;;Department of Geology, University of Leicester, Leicester LE1 7RH, UK;;Geotek Ltd, Faraday Close, Drayton Fields, Daventry, Northants. NN11 5RD, UK |
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| Abstract: | ABSTRACT Recently developed effective stress-controlled geophysical property models are used in passive-margin slope instability analyses including simulated earthquake motion. The pressure–temperature (P–T) history of sediment-hosted gas hydrate may significantly alter the geophysical property profile of the sediment column (e.g. metastable cement or increased pore pressures). This can result in significant amplification of earthquake ground motion, and thus seabed instability, where hydrates are present. Published studies suggest destabilization of these high-pressure/low-temperature sediment-hosted hydrates could trigger catastrophic slope failures with consequent liberation of 'greenhouse' gases and significant effects on global climate. To provide improved ground models for slope instability analyses we are investigating the influence of P–T history on hydrate distribution in sediments through the development of laboratory techniques to enable geophysical quantification of hydrate morphology and fabric on hydrate stability. |
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