What is a landslide?   [Top]

  Landslides are flows of rock, earth, and debris on slopes (mainly due to gravity). Landslides can also be called mud flows, mudslides, earth failures, slop failures, etc. They occur when there is a large amount of movement in the ground that causes rocks to fall. Landslides can occur on virtually any terrain (given the right soil, moisture, and slope angle conditions). Landslides serve to redistribute soil and sediment in a way that can be a slow, gradual slide or an abrupt collapse. They can be started by rains, earthquakes, floods, or other natural causes. They can also be triggered by human-made causes such as terrain cutting and filling, grading, and excessive development. The main contributor to landslide formation is gravity, but some other factors include oversteepened slopes (caused by river, glacier, or ocean wave erosion), saturated ground, earthquakes, or ash deposits from volcanoes. Though the term landslide is used to mean 'any rapid movement of rocks and sediment downslope', it is actually more accurate to use the term 'mass wasting' to refer to the variety of mass movement.

There are three basic types of mass wasting:

1. Falls - rocks fall or bounce through the air.
2. Slides - rock or sediment slides along Earth's surface.
3. Flows - sediment flows across Earth's surface.

  What kind of damage does a landslide cause?   [Top]

  Landslides cause damage to houses, cars, et cetera As these natural disasters move along, they pick up houses cars, and even trees. The results of this include blocked passages and flooding. In some cases, only the rail or pavement is mangled, in others a house or building crushed, but most damage is permanent. They affect utilities, transportation, and all other forms of infrastructure. A landslide resembles a snow avalanche, only with a louder rumbling noise. Landslides are capable of generating enough force and momentum to wipe anything in its path. Landslides cause one to two billion dollars in damage each year in the US and claim as many as fifty lives per year. No region of the country is safe from landslides, whether caused by natural or human-made forces.

  where do landslides occur?   [Top]

  Landslides can occur in any area that contains fractured materials near the top of a steep slope. Areas near mountains usually have the most severe landslide problems. Since the factors which affect landslide formation can be natural or man-made, they can occur in any area in which the land has been altered. They occur in all fifty states, and more than half the states have rates sufficient to be classified as a significant natural hazard.

  How can landslides be prevented?   [Top]

  Although it is nearly impossible to remove some of the physical causes (gravity, earthquakes), precautions can be taken to reduce the likelihood of a landslide. Such precautions include enforcement of land-use management regulations and geologic investigations. The U.S. Geological Survey is putting forth effort to study landslide risks. Many organizations deal with landslides as part of flood control, erosion control, road stabilization, and other programs. As development increases, so does building in areas susceptible to landslides. Sadly, this increases the risk of landslide occurances.