P-wave velocities and applied bed thickness and velocity changes for synthetic seismograms, ODP Leg 188 and Leg 119 sites

• Main Authors: Handwerger, David A, Cooper, Alan K, O'Brien, Philip E, Williams, Trevor J, Barr, Samantha R, Dunbar, Robert B, Leventer, Amy, Jarrard, Richard D
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 2004
• Subjects: 119-742; 188-1165; 188-1166; COMPCORE; Composite Core; Indian Ocean; Joides Resolution; Leg119; Leg188; Ocean Drilling Program; ODP; Prydz Bay; Antarc*; Antarctica
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.780548; https://doi.org/10.1594/PANGAEA.780548

Synthetic seismograms provide a crucial link between lithologic variations within a drill hole and reflectors on seismic profiles crossing the site. In essence, they provide a ground-truth for the interpretation of seismic data. Using a combination of core and logging data, we created synthetic seismograms for Ocean Drilling Program Sites 1165 and 1166, drilled during Leg 188, and Site 742, drilled during Leg 119, all in Prydz Bay, Antarctica. Results from Site 1165 suggest that coring penetrated a target reflector initially thought to represent the onset of drift sedimentation, but the lithologic change across the boundary does not show a change from predrift to drift sediments. The origin of a shallow reflector packet in the seismic line across Site 1166 and a line connecting Sites 1166 and 742 was resolved into its constituent sources, as this reflector occurs in a region of large-scale, narrowly spaced impedance changes. Furthermore, Site 1166 was situated in a fluvio-deltaic system with widely variable geology, and bed thickness changes were estimated between the site and both seismic lines.