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.
When soil, rock, and other earth debris can no longer hold it together and gives way to gravity, landslides happen. The downward force of a landslide can move slowly, (a mere millimeters per year) or quickly with disasterous effects. Landslides can even occur underwater, causing tidal waves and damage to coastal areas.