Figure 10. Sidescan -sonar imagery and chirp seismic-reflection profile on the inner shelf offshore of North Island. See figure 4 for figure location. Top: Perspective view of sidescan-sonar imagery draped over bathymetry, showing the moderate to high backscatter ridges characteristic of the area. Bottom: Chirp seismic-reflection profile shows large, asymmetric ridges of modern sediment with steeper sides facing south, and the transgressive surface (blue) exposed in the swales. Depth is approximate and assumes a seismic velocity of 1500 m/sec. Figure modified from Baldwin and others (2006, their figure 3 in Data Repository).