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Victoria University Antarctic Research Expedition Science and Logistics Reports 2001-02: VUWAE 46

New Harbour Seismics

New Harbour Seismics

Figure 5 shows an example of the brute stack (preliminary data) form the NHS-1 line. The seafloor is seen to dip down to the east reaching a maximum water-depth pf c. 340m at the eastern end of the line. A brute stack of the NHS2 data (Fig. 6) shows a seafloor high at the western end of the line at about c. 180m depth with the sea-floor depth increasing to c. 280m to the east. Sub-seafloor strata dip east. The quality of the seismic data is not as good as "normal" land-seismic data, but is the best expected given the complex physical (ice-water-sediment interface) environment. It is widely acknowledged that flexure of sea-ice significantly complicates the seismic arrival pattern. Major noise arrivals include: large amplitude sea-floor multiples, airwave arrivals, side scatter reflections of local valley topography, and a multiple due to either a very low velocity layer below the sea-floor, or else a complex P-SV converted wave. Sedimentary reflections are visible at the eastern ends of both of the New harbour lines, with stacking velocities of 1800 m/s and above the multiple, up to 0.4ms.