Video Worksheet 8. In 1940, what area of the California coast began to slide? 1. What was the trigger of the Nevado del Ruiz event? Point Fermin landslide Volcanic eruption 9. Give the name of the specific type of mass wasting here: 2. Define “Mass Wasting” Slump Downslope movement of , regolith, and rock under the influence of gravity 10. How can this area be stabilized?

Compaction, regarding, at great expense! 3. What are the driving forces of mass wasting? Gravity, water, loading

11. At Portuguese Bend, what are 4. List some naturally steep slopes: the causes of mass wasting? coasts Old slide stream channels glacial valleys building—fill dirt overloaded the old slide

5. What human influences contribute to mass wasting? 12. What mitigation techniques Road building (efforts to minimize the impact) logging are used at Portuguese Bend? development landscaping Concrete and steel nails at base of slide 6. What does water do? Above ground utilities Lubricates particles Isolate house from ground Separates particles Drain water from water table Overloads slope with weight —rock structures to reduce erosion at shoreline

13. Which seems to have been 7. What type of mass wasting completely ineffective? causes the most economic Concrete and steel nails at base of damage? slide Creep 14. Which seems to have made the greatest impact? Drain water from water table 15. What type of mass wasting 21. What can be done to mitigate affects Wrightwood, California? potential mass wasting?

Mudflows, debris flows Careful Removal of slide material before 16. How large of particles can be building carried by this type of mass wasting? 22. What is the main concern, and From to automobiles can it be dealt with effectively?

Slump, landslide 17. In what manner do the residents No, because it continues onto of Wrightwood deal with their adjacent land that developer has mass wasting problem? no control over. debris from channel Build higher banks on channel 23. At Portuguese Bend, what is the main cause of the mass wasting?

18. Why is Wrightwood so Road building vulnerable? San Andreas fault has pulverized nearby material. 24. How fast do rock slides/rock 19. In mountainous areas, what type avalanches travel? of mass wasting is the biggest hazard? Several hundred km/hr Rock fall, rock slide, avalanche

20. In an area to be developed, what 25. What do humans do to contribute clues are gathered to determine to mass wasting? the likelihood of mass wasting Steepen slopes, add excess water damage? Look for evidence of creep and slump