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1 Earth Sciences Department, University of California, Santa Cruz, California 95064, USA
2 Amoco Exploration and Production Technology Group, Tulsa, Oklahoma 74102, USA
3 Institute of Geophysics, University of Texas, Austin, Texas 78759, USA
The application of three-dimensional seismic reflection and coherence imaging to the study of the décollement zone of the Barbados Ridge accretionary complex has provided new insights into the relationships among internal structure, fluid flow, and previously unrecognized strike-slip faulting. Combined coherence and seismic amplitude imaging of the décollement zone reveal anomalous northeast-trending lineaments parallel to and abutting zones of high- amplitude, negative-polarity reflections. Analysis of these lineaments shows them to be penetrative structures dipping southeast with apparent reverse dip-slip offset. Isopach mapping of the accretionary wedge indicates significant right-lateral displacement across these structures. These faults apparently channel fluid flow within the décollement zone, and the prominent northeast- trending conduits so formed are readily visible as high-amplitude, negative-polarity reflections. Additionally, north-northeast– trending zones of variable coherence and high positive amplitude are inferred barriers to up-structure fluid-migration pathways.
Movement along strike-slip structures probably alternates with displacement along the décollement zone. Northeast- trending strike-slip faults extend for >13 km, crossing the length of the survey area and into the incoming oceanic plate. Active arc-oblique strike-slip faulting of the décollement zone beneath the Barbados Ridge accretionary wedge implies a stress regime in that 
1 is fixed and 2 and 3 either transpose with time or are nearly equal. This state of stress may be a common occurrence in forearc tectonism and may have led to the formation of many, as yet unrecognized, arc-oblique strike-slip faults at convergent margins.
Key Words: active tectonics • décollement • faults and faulting • seismic methods • subduction zones
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  Y. Yamada, K. Baba, and T. Matsuoka Analogue and numerical modelling of accretionary prisms with a decollement in sediments Geological Society, London, Special Publications, January 1, 2006; 253(1): 169 - 183. [Abstract] [PDF]
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 Y. Ogawa and P. Vrolijk Control of internal structure and fluid-migration pathways within the Barbados Ridge decollement zone by strike-slip faulting: Evidence from coherence and three-dimensional seismic amplitude imaging: Discussion Geological Society of America Bulletin, January 1, 2006; 118(1-2): 253 - 254. [Full Text] [PDF]
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C. DiLeonardo and J. C. Moore Control of internal structure and fluid-migration pathways within the Barbados Ridge decollement zone by strike-slip faulting: Evidence from coherence and three-dimensional seismic amplitude imaging: Reply Geological Society of America Bulletin, January 1, 2006; 118(1-2): 255 - 256. [Full Text] [PDF]
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G. Wallace, J.C. Moore, and C.G. DiLeonardo Controls on localization and densification of a modern decollement: Northern Barbados accretionary prism Geological Society of America Bulletin, March 1, 2003; 115(3): 288 - 297. [Abstract] [Full Text] [PDF]
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