10.4 Erosion and Deposition by Mass Movement

1. 10.4 Erosion and Deposition by Mass Movement

2. Describe places where the warning sign “Watch for falling rocks!” would be necessary or useful.

3. Rapid Mass Movement • Landslide – the sudden rapid movement of a large amount of material downslope. • Slump • Most common landslide • Occur when a block of material moves downslope over a curved surface.

4. Mass Movement • The movement of any material, such as rock, soil, or snow, downslope.

5. Angle of Repose • The steepest angle, or slope, at which loose material no longer moves downslope.

6. Rapid Mass Movement • Rock fall – loose rocks fall down a steep slope.

7. Landslides ..\..\video clips\10.4 mass movement\Landslides__Products_of_Opposing_Forces__Heat_vs__Gravity.asf

8. How can a landslide affect wildlife habitats? A landslide can change a human or wildlife habitat by carrying away plants and animals or by burying a habitat.

9. Rapid Mass Movement • Mudflow – • mass movement of a large mass of mud. • Happens when a large amount of water mixes with soil and rock.

10. Rapid Mass Movement • Creep – • Extremely slow movement of material downslope. • Water loosens soil, plant roots act as wedges that force rocks and soil apart, burrowing animals loosen rock and soil particles.

11. Why must city planners determine the risk of mass movement when deciding how to use land? It is not advisable to build near a known hazard. The frequency and severity of mass movement would need to be considered when making this decision.

12. Review Questions • What is mass movement? Mass movement is the movement of any material downslope. 2. How do mass movements affect humans? Mass movements affect humans by affecting the habitats in which humans live. Mass movements can destroy houses and roads.

13. Which types of mass movement are most dangerous to humans? • Rapid mass movements, such as rock falls, landslides, and mudflows are the most dangerous types of mass movements for humans because large amounts of material move rapidly downslope without warning. • Creep is a type of mass movement that occurs slowly. Describe the kinds of effects that you think creep has on trees, buildings, and roads. • Creep slowly changes trees, buildings, and roads. The trunks of trees may appear ot bend as they grow. Buildings may become unstable or their foundations may crack. Roads may crack as a result of creep.