surname, attested from late 12c., probably meaning bald head; cf. Wyclif Stye up, ballard, where Coverdale translates Come vp here thou balde heade [2 Kg.2:23-24, where God kills 42 children for making fun of Elijah's lack of hair.]
A slump is a form of mass wasting that occurs when a coherent mass of loosely consolidated materials or rock layers moves a short distance down a slope. Movement is characterized by sliding along a concave-upward or planar surface. Comments.
The movement, especially in the case of slides and slumps, is along a failure plane. The failure plane may be a well-defined layer of clay or rock upon which sets the destabilized surface material. Humans induce mass movement when subjecting a slope to a load that exceeds its ability to resist movement.