How does the coastal landslide hazards map relate to a surficial geology map?
Coastal landslide hazards are most likely to occur in areas with surficial sediments of the Presumpscot Formation (composed mostly of glaciomarine mud and silt). While the Presumpscot Formation can occur from Kittery to Eastport, the distribution of this surficial sediment is patchy. A surficial geology map will show where the Presumpscot Formation is known to occur along the shoreline. Landslides are much less likely to occur in sand and gravel deposits (glacial till and outwash) that are shown on a surficial geology map. These coarse-grained sediments are still subject to bluff erosion, so using a surficial geology map alongside either a coastal bluffs or landslide hazards map is a good idea when making land-use decisions.
