Changing Earth's Surface
Weathering, erosion, and deposition act together in a cycle that wears down and builds up Earth's surface. Gravity, running water, glaciers, waves, and wind are all causes of erosion. The material moved by erosion is sediment. Weathering and erosion produce sediment. Mass movements change Earth's surface. There are different types of mass movement such as landslides. mudflows, slump, and creep. Mass movements can be rapid or slow.
LandslidesLandslides are the most destructive kind of mass movement. Landslides happen when rock and soil slide quickly down a steep slope. Huge pieces of rock are in some landslides. Other landslides have only small amount of rock and soil.
|
MudflowsA mudflow is the rapid downhill movement of a mixture of water, rock, and soil. Some mudflows can be as high as 60%. Mudflow usually happen after heavy rain in normally dry areas. Mudflows can be very dangerous. Earthquakes can make both mudflows and landslides.
|
SlumpA slump is a mass of rock and soil that suddenly slip down a slope. Slumps may sound like landslides, but slumps move down in one large mass unlike landslides. Slumps usually happen when water soaks to the bottom of soil that is rich in clay.
|
CreepA creep is the very slow downhill movement of rock and soil. Creep is often the results for freezing and thawing of water in cracked layers of rock under the soil. A creep is so slow you can barely notice it. You can tell the effects of a creep by the objects around it, such as telephone poles and fence posts.
|