Subglacial Water Pressures and the Shape of Subglacial Conduits

• Published in: Journal of Glaciology
• Main Authors: Hooke, Roger LeB., Laumann, Tron, Kohler, Jack
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1990
• Subjects: Earth-Surface Processes; Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/s0022143000005566; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000005566

Abstract Measured subglacial water pressures are frequently higher than theoretical values calculated by assuming that subglacial conduits are straight and either circular or semi-circular in shape. While this may be attributed to errors in the estimates of conduit roughness or ice viscosity, we suggest here an alternative explanation: namely, that the conduits are actually broad and low rather than semi-circular. Good agreement between measured and calculated pressures can be obtained by assuming that the cross-sectional shape of conduits resembles the space between the arc of a circle and its chord. The angle subtended by the arc, θ, is treated as an adjustable parameter. In four cases studied, θ ranged from 2° to 36°.