cliffline

Cliffline, also known as cliff line, is a geomorphological term describing the line along which a cliff face meets adjacent landforms or waters. It marks the upper boundary of exposed bedrock where steep slopes or vertical faces begin. In coastal areas, the cliffline corresponds to the limit of actively eroding rock cliffs formed by wave action, weathering, and mass wasting; inland, it can delineate escarpments along plateaus, canyons, or river valleys.

The position of the cliffline is not fixed; it migrates due to erosion, weathering, rockfall, and changes in sea level or climate. Lithology, structural geology (faults, folds, bedding) and coastal process energy govern the curvature and retreat rate. Steep, resistant rocks host more stable clifflines; softer, fractured rocks retreat faster, creating irregular lines with headlands and embayments.

Clifflines are used in mapping and land management; on topographic and coastal maps they help define boundaries for development, hazard assessment, and habitat zoning. They also serve as ecological boundaries: the microclimate at the cliffline supports specialized plant and animal communities sheltered from inland conditions.

Techniques such as aerial photography or LiDAR are used to delineate clifflines precisely for planning and monitoring shoreline change.