1. Forces of Erosion
The Agents of Erosion and Mass Movement sculpt the Earth’s surface into landforms.
Mass Movement and Erosion processes can be natural occurrences, or be caused by humans.
Undercutting of hillsides during road and home construction are major human causes of these two processes.

2. Kinds of Mass Movement
1. Landslides
2. Mudflow
3. Slump
4. Creep

3. Mass Movement or Wasting
Mass movement or wasting is caused by gravity, the force that pulls everything toward the center of the Earth.
Mass movement can be rapid or slow.

4. Landslides
Landslides occur quickly, causing soil and rock to slide quickly down a steep sloop. Some landslides contain huge masses of rock.
Landslides are common where builders have cut highways through hills or mountains.
Can be caused by earthquakes.

5. Landslide

6. Mudflow
Mudflows are rapid downhill movement of a mixture of water, rock, and soil.
Water content can be as high as 60%
Mudflows occur after heavy rains.
Can be triggered by earthquakes.

7. Mudflow

8. Slump Mass of rock and soil sudden slips down a slope.
Moves down in one large mass.
Often cause by water soaking the base
of a mass of soil rich in clay.

9. Slump

10. Creep
Creep is the slow downhill movement of rock and soil. Occurs on steep and gentle slopes.
Effects of creep are visible in objects such as telephone poles, gravestones, fence posts.
Caused by the freezing and thawing of water in cracked layers of rock under the soil layer.

11. Creep