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.
Quakes occur when the frictional stress of the movement exceeds the strength of the rocks, causing a failure at a fault line. Violent displacement of the Earth's crust follows, leading to a release of elastic strain energy. This energy takes the form of shock waves that radiate and constitute an earthquake.