1. Changing Earth’s Surface The wearing down of Earth’s surface is called erosion. Erosion is the process by which natural forces move weathered rock and soil from one place to another. Causes of Erosion -gravity -running water -waves -glaciers -wind

2. Building Up Earth’s Surface The material moved by erosion is sediment. -can consist of rock, soil, or remains of plants and animals -produced be erosion and weathering Deposition occurs where the agents of erosion deposit or lay down sediment. -changes the shape of the land

3. Erosion and deposition act together in a cycle that wears down and builds up Earth’s surface. Erosion and deposition are at work everywhere on Earth. As a mountain wears down in one place, new landforms build up in other places. The cycle of erosion and deposition is never-ending.

4. Erosion occurs constantly, even while mountains are forming Erosion wears down mountains and fills valleys with sediment. Working together, erosion and deposition have almost leveled the land surface When new mountains or plateaus form, the cycle of erosion begins all over again. Cycle of Erosion & Deposition

5. Mass Movement Gravity is the force that pulls objects toward the center of the Earth. Gravity is the force that moves rock and other materials downhill. Gravity causes mass movement. Mass movement is any one of several processes by which gravity moves sediment downhill. Mass movement can be rapid or slow.

6. Landslides -Most destructive type of mass movement -Occurs when rock and soil slide quickly down a steep slope Types of Mass Movement http://www.youtube.com/watch?v=L12JeA z9YN0

7. -Rapid downhill movement of water, rock, and soil -Can contain up to 60% of water -Often occur after heavy rains -Can occur on gentle or steep slopes Mudflow

8. -A mass of rock and soil that suddenly slips down a slope in one solid mass. -often occurs on a steep slope when water soaks the bottom of clay rich soil Slump

9. Creep -The very slow movement of rock and soil. -can occur on gentle or steep slopes -occurs from the freezing and thawing of water in cracked layers beneath the soil

11. Types of Mass Movement SpeedSlope Landslide Mudflow Slump Creep