Uninterpreted high-resolution "boomer" seismic profile illustrates the poor acoustic contrast between the Holocene sediment cover and the Pleistocene exposure surface. The poor contrast is typical throughout the region and is attributed to the karst and weathered nature of the underlying pre-Quaternary bedrock. The offshore Holocene sediment thickness is usually less than 2 to 3 m, corresponding with the higher-relief portions of the sand waves or ridges seen here.