Chapter 12 sec 4 vocabulary Mass movement Angle of Repose Lahars Rapid Mass movement Rock fall Landslide Slump Mudflow Slow Mass Movement Creep

Mass movement Is a movement of a section of land (any material such as, rock, soil, or snow) down a slope.

Angle of Repose The steepest angle, or slope, at which loose material will not slide downslope.

Lahars Mudflows of volcanic origin are called lahars. Lahars can travel at speeds of 80 km/h and can be as thick as cement.

Rapid Mass Movement The sudden mass and fast movement of a tract of land.

Rock Fall A sudden rapid movement of loose rocks that fall down a steep slope.

Landslide The sudden and rapid mass moment of rock and soil down a slope.

Slump The most common type of landslide. It occurs when a block of material moves downslope over a curved surface.

Mudflow The rapid movement of a large mass of mud or rock mixed with a large amounts of water.

Slow mass movement Land movement that happens slowly over time. Because it happens more slowly more material is moved over time.

Creep A type of slow mass movement where material moves downhill extremely slow. Could happened over months, or years.