movement is mainly through the air in rock and debris falls. slides and flows move
on the surface both down and out. more rapid are more dangerous.
slide is distinguished from a flow by being a solid mass moving along a single
failure plane or fracture zone.
further classification is based on nature of material move. dry material can produce
hazardous movements ranging from rock and debris falls and slides to slumps.
hazardous flows occur when earth or rock is mixed with water to form earth flows
mudflows and lahars.
both landslides and landslips occur in solid rocks and weathered material. in a
landslide, the plane along which movement takes place in cloned and material
moves in mass, breaking up where it comes to rest.
in a slip or slump movement is rotational along a curved slip plane and results in
an arcuate slip face and unbroken toe which rises towards the end of the slipped
mass. occur in areas with alternating permeability.