GEOLOGY

Detailed explanation-1: -Landslides can be initiated in slopes already on the verge of movement by rainfall, snowmelt, changes in water level, stream erosion, changes in ground water, earthquakes, volcanic activity, disturbance by human activities, or any combination of these factors.

Detailed explanation-2: -Landslides are actually a very extreme, fast-acting method of erosion: They transfer sediment down a slope and deposit it at the end of their path. The sediment a landslide deposits is known as its talus. The five agents of erosion are wind, waves, running water, glaciers and gravity.

Detailed explanation-3: -Gravity can pull soil, mud, and rocks down cliffs and hillsides. This type of erosion and deposition is called mass wasting. Landslides are the most dramatic, sudden, and dangerous types of mass wasting and cause $1 billion to $2 billion damage in the United States each year.

Detailed explanation-4: -Landslides, avalanches, and mudflows are examples of dangerous erosion by gravity. Slump and creep move material slowly downslope. Plants, retaining walls, and good drainage are ways to help prevent landslides.