Digital Data for Coastal Bluff and Landslide Hazards
This dataset contains line data describing the shoreline type and relative stability of bluffs along a section of the Maine coast mapped at a scale of 1:24,000. The Maine Geological Survey used this dataset to produce Coastal Bluffs Maps and Coastal Landslide Hazards Maps. A bluff is defined as a steep shoreline slope formed in sediment (loose material such as clay, sand, and gravel) that has three feet or more of vertical elevation just above the high tide line. Shoreline segments are classified as either being bluff, non-bluff, or unmapped or undetermined. Bluffs are classified as either (1) ledge (exposed bedrock outcrops); (2) armored (seawall, riprap, gabion, bulkhead, etc.); (3) salt marsh; (4) beach, mud flat, or other loose sediment; or (5), unmapped or undetermined. The relative stability of a bluff face is classified as being either (1) not a bluff, (2) stable, (3) unstable, (4) highly unstable, or (5) unmapped or undetermined. This classification is based on observed features that reflect recent activity on the bluff face. The landslide hazard is given by line data describing the internal stability of sediment bluffs along Maine's shoreline. The landslide hazard is classified by one of the following: (1) the bluff is the site of a past historical or photo interpreted landslide; (2) the bluff has an elevated risk of a landslide based on field observation; (3) the bluff has an elevated risk of a landslide based on aerial photo interpretation, but needs field assessment; (4) there is no landslide potential; or (5) the landslide potential is unmapped or undetermined.
The digital data may not include information from the most recently published coastal bluffs maps. This data will be updated periodically but may be out of step briefly with published maps. The user should check the source attributes associated with the coastal bluffs data (points/lines/polygons) and verify that the digital data reflects the current published map for the quadrangle. The user can view the most recently published maps or check the source for the cited open-file map in the Bibliography of Maine Geology by searching for the open-file number (e.g. 04-93) in the keyword search source field.
Instructions for Downloading Digital Coastal Bluffs Data
- Using a web browser, go to the Maine Office of GIS Data Catalog. A topical listing of digital data layers will appear. Scroll down to the section titled Geological and geophysical.
- The dataset is named Coastal Bluff Hazards.
- Click on the icons in the "Download" column to:
- View metadata.
- Download a .zip file of the bluff hazards shapefile.
- Download a .kmz file to view the data using Google Earth.
Last updated on March 15, 2013