Limits of tidal energy dissipation by fluid flow in subsea formations |
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Authors: | Kelin Wang,Garth van der Kamp,& Earl E. Davis |
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Affiliation: | Pacific Geoscience Centre, Geological Survey of Canada, 9860 W. Saanich Rd., Sidney, BC, Canada V8L 4B2. E-mail:;, National Hydrology Research Institute, Environment Canada, 11 Innovation Blvd, Saskatoon, Sask, Canada S7N 3H5. E-mail: |
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Abstract: | Tidal loading causes fluid flow through permeable seafloor and between regions of contrasting elastic properties or porosity within subsea formations. We examine theoretically the dissipation of energy by these flows and its global significance as a mechanism for tidal energy dissipation. Expressions are given for energy dissipation rates in layered formations due to vertical flow caused by tidal loading, but the results can be used to constrain dissipation by other flow patterns. We consider flow near the seafloor, in gas-bearing sediments, and in highly fractured permeable igneous crust. Energy dissipation by the first two mechanisms is negligibly small globally, although it may be locally significant under extreme conditions. Under favourable conditions, flow in fractured crust may have greater energy dissipation, but the total amount is limited by the thickness of the permeable layer. Based on our current understanding of subsea hydrogeology, tidally induced flow in subsea formations appears to make little contribution to the observed global tidal energy dissipation. |
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Keywords: | bulk modulus fluids in rocks heat flow oceanic crust permeability tides |
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