Figure F5. An east-west slice through the 3-D data volume, converted to depth using a 3-D velocity model determined through tomographic inversion of first arrivals recorded on OBSs (Arsenault et al., 2001). Sites to be drilled during Leg 204 are shown. Primary Site HR2alt is in a similar setting as HR2altB, which has been approved by the Pollution Prevention and Safety Panel as a backup site in case we encounter difficulties at proposed Site HR2alt. The BSR and reflectivity of underlying strata are brighter at proposed Site HR2alt than at HR2altB. The solid green line marks the boundary between low-amplitude, low-frequency, chaotic reflectivity, interpreted to be highly deformed sediments of the accretionary complex, and overlying reflective strata. This boundary corresponds to a rapid increase in velocity from <1.8 to >2.0 km/s. The dashed green line delimits a zone of intermediate reflectivity. Reflections marked A, B, B', and C and anticlines A and B are discussed in the text. VE = vertical exaggeration.