Figure F8. Velocity modeling of multichannel seismic (MCS) reflection data to determine velocities in upper 800 m of sedimentary section at Site 1276, where no cores or downhole logs were obtained. A. Section of a prestack time migration of SCREECH Line 2 together with a common midpoint (CMP) gather close to Site 1276. Colored lines indicate picks used for velocity modeling described in text. B. 1-D velocity-depth function derived from velocity modeling (red line) plotted together with laboratory measurements of vertical P-wave velocity from Site 1276 (blue dots) and a moving average of these measurements calculated with 100-m window (blue line) for display purposes. Velocities derived from velocity modeling were used above the first laboratory measurement (<800 mbsf) to create synthetic seismograms.

Figure F8. Velocity modeling of multichannel seismic (MCS) reflection data to determine velocities in upper 800 m of sedimentary section at Site 1276, where no cores or downhole logs were obtained. A. Section of a prestack time migration of SCREECH Line 2 together with a common midpoint (CMP) gather close to Site 1276. Colored lines indicate picks used for velocity modeling described in text. B. 1-D velocity-depth function derived from velocity modeling (red line) plotted together with laboratory measurements of vertical P-wave velocity from Site 1276 (blue dots) and a moving average of these measurements calculated with 100-m window (blue line) for display purposes. Velocities derived from velocity modeling were used above the first laboratory measurement (<800 mbsf) to create synthetic seismograms.