The dynamics of a landslide

The onset of slip of a landslide may be mathematically modeled as the sudden detachment of a block of softer material initially bonded to the side of a mountain. Its subsequent motion is slowed by friction and by energy dissipation in the block due to its change of shape, which commences when the block reaches the bottom of the mountain. Since the bottom is a horizontal plane, the block will continue to slide along it until its kinetic energy is exhausted or it collides with an obstacle. A numerical example shows that the front of even a relatively small landslide can travel far from the base of the mountain.