Generally, high backscatter intensity is associated with rock or coarse-grained sediment, and low backscatter intensity characterizes finer grained sediments. Direct observations, using bottom photography or video and sampling techniques such as grab sampling or coring, are needed to verify interpretations of the backscatter intensity. These data are draped over a shaded relief image created by vertically exaggerating the topography four times and then artificially illuminating the relief by a light source positioned 45 degrees above the horizon from an azimuth of 350 degrees. The resulting image displays light and dark intensities within each color band that result from a feature's position with respect to the light source. The shaded relief image accentuates small features that could not be effectively shown by contours alone at this scale.
Some features are artifacts of data collection and environmental conditions.
They include small highs and lows and unnatural looking features or patterns oriented parallel or perpendicular to survey tracklines. The orientation of the tracklines are identified by the faint parallel stripes in the image. White areas are areas of no data. In some areas, the backscatter intensity shows stripes parallel to the survey tracklines. This produces high backscatter intensity in the inner part of the swath and a rapid change to reduced intensity at the outer part.