| Abstract: | We present results from an analysis of anisotropy in marine sediments using walkaway vertical seismic profiles from the Blake Ridge, offshore South Carolina. We encountered transverse isotropy (TI) with a vertical symmetry axis in a gas-hydrate-bearing unit of clay and claystone with Thomsen parameters ?? = 0.05 ?? 0.02 and ?? = 0.04 ?? 0.06. TI increased to ?? = 0.16 ?? 0.04 and ?? = 0.19 ?? 0.12 in the underlying gas zone. Rock physics modeling suggests that the observed TI is caused by a partial alignment of clay particles rather than high-velocity gas-hydrate veins. Similarly, the increase of TI in the gas zone is not caused by thin low-velocity gas layers but rather, we speculate, by the sharp contrast between seismic properties of an anisotropic sediment frame and elongated gas-bearing pore voids. Our results underscore the significance of anisotropy for integrating near-vertical and wide-angle seismic data. |
| Genre: | Article |
| ProdID: | 70025472 |
| Citation Author: | Pecher, I. A.; Holbrook, W. S.; Sen, M. K.; Lizarralde, D.; Wood, W. T.; Hutchinson, D. R.; Dillon, W. P.; Hoskins, H.; Stephen, R. A. |
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| Citation Issue: | 14 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geophysical Research Letters |
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| Citation Search Results Text: | Seismic anisotropy in gas-hydrate- and gas-bearing sediments on the Blake Ridge, from a walkaway vertical seismic profile; 2003; Article; Journal; Geophysical Research Letters; Pecher, I. A.; Holbrook, W. S.; Sen, M. K.; Lizarralde, D.; Wood, W. T.; Hutchinson, D. R.; Dillon, W. P.; Hoskins, H.; Stephen, R. A. |
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| Citation Volume: | 30 |
| Citation Year: | 2003 |
| Type: | citation/reference |
| Text: | Seismic anisotropy in gas-hydrate- and gas-bearing sediments on the Blake Ridge, from a walkaway vertical seismic profile; 2003; Article; Journal; Geophysical Research Letters; Pecher, I. A.; Holbrook, W. S.; Sen, M. K.; Lizarralde, D.; Wood, W. T.; Hutchinson, D. R.; Dillon, W. P.; Hoskins, H.; Stephen, R. A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 2003 00:00 -0600 |
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