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.
Landslides occur when gravity overcomes the force of friction. Several common causes of landslides are: 1  Water: Perhaps the most common trigger of a landslide, water reduces the friction between the bedrock and the overlying sediment, and gravity sends the debris sliding downhill. 2  In sand and clay soils, a small amount of water may increase stability.