{ The Effect of Gravity on Erosion and Deposition Agents of Weathering and Erosion

 Gravity not only influences the movement of water and ice but also causes rocks and soil to move downslope.  Mass Movement: the movement of any material, such as rock, soil, or snow, downslope Gravity

 Angle of repose: the steepest angle, or slope at which loose material will not slide downslope  Characteristics that affect angle of repose  Size  Weight  Shape  Moisture level Angle of Repose

1. Rock falls: when loose rocks fall sown a steep slope 2. Landslides: the sudden and rapid movement of a large amount of material downslope  Slump: when a block of material moves downslope over a curved surface  Heavy rains  Deforestation  Construction on unstable slopes  Earthquakes Rapid Mass Movement

3. Mudflows: large amounts of water mixes with soil and rock 4. Lahars: volcanic ash mixes with heavy rains and produces a mudflow Rapid Mass Movement Continued

 Creep: extremely slow movement of material downslope  Water loosens soil  Plant roots  Burrowing animals Slow Mass Movement

 Gravity causes rocks and soil to move downslope.  If the slope on which material is greater than the angle of repose, mass movement will occur.  Four types of rapid mass movement are rock falls, landslides, mudflows, and lahars.  Water, plant roots, and burrowing animals can cause creep. Summary