Rotational slide (slump)
A slump has a curved (circular) sliding surface which drops almost vertically in the crack recess. It usually has only a limited material volume which is only slightly transformed. The sliding surface is often formed in loose loamy and clayey material. Typical crevasses and fissures are visible in the top half of the slump. At the face the mass is compressed, disintegrated and, if highly saturated with water, is transformed into muddy debris flows or slope debris flows in certain situations (particularly with clay silt F. sand).