Use of Ganna Ray Attenuation; Acoustic Velocity; and Electrical Resistivity in the Extracation of Sediment Physical Properties
Sediment physical properties, such as porosity, shear strength, shear modulus, and grain size, from six different geographical marine environments (Central Arctic Ocean, Central Scotian Shelf, Gulf of Mexico, Caribbean Sea, North-Eastern Pacific, Western Equatorial Pacific and Mid-Atlantic Ridge) we...
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DigitalCommons@URI
2003
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| Online Access: | https://digitalcommons.uri.edu/theses/1118 https://doi.org/10.23860/thesis-altmann-veith-2003 https://digitalcommons.uri.edu/context/theses/article/2124/viewcontent/thesis_altmann_veith_2003.pdf |
| Summary: | Sediment physical properties, such as porosity, shear strength, shear modulus, and grain size, from six different geographical marine environments (Central Arctic Ocean, Central Scotian Shelf, Gulf of Mexico, Caribbean Sea, North-Eastern Pacific, Western Equatorial Pacific and Mid-Atlantic Ridge) were analyzed and correlated with non-destructive measurements of compressional wave velocity, bulk density and electrical resistivity. In coarse grained sediments (median grain diameter >4 μm) with a sand fraction greater than 15%, larger grain size is associated with higher velocity. In fine grained sediments (median grain diameter < 4 μm) velocity does not correlate with median grain size. However, a pronounced linear relationship exits between compressional wave velocity and percent clay fraction (grain diameter < 2 μm) regardless of sediment grain size. The use of electrical resistivity is limited for predicting porosity in unconsolidated sediments. In general, the trend of decreasing sedimentary porosity with increasing electrical resistivity, is consistent with previous observations (e.g., Archie, 1942). However, the trends are sediment-type dependent and therefore resistivity measurements cannot be used as sole predictor of porosity. Compressional wave velocity and bulk density, expressed as the elastic parameter b (v2p * ρB) correlate well with miniature vane shear data. These non-destructive measurements can be used to predict undrained shear strength. |
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