The term landslide is a general term for a variety of downslope movements of earth materials. Some slides are rapid, occurring in seconds, whereas others may take hours, weeks, or even longer to develop. A rotational slump is characterized by the movement of a mass of weak rock or sediment as a block unit along a curved slip plane. These slumps are the largest type of landslide in Ohio, commonly involving hundreds of thousands of cubic yards of material and extending for hundreds of feet. Major components of a rotational slump.
Rotational slumps have an easily recognized, characteristic form.
Trees on these rotated blocks may be inclined upslope, toward the top of the hill. Characteristically, an earthflow involves a weathered mass of rock or sediment that flows downslope as a jumbled mass, forming a hummocky topography of ridges and swales. Trees may be inclined at odd angles throughout the length of an earthflow. Earthflows are most common in weathered surface materials and do not necessarily indicate weak rock. They are also common in unconsolidated glacial sediments.