MASS WASTING Movement of material due to gravity Causes more property damage than all other geological disasters

Slopes Factors: (1)Slope material and (2) angle steeper = more likely to move less friction between particles = more likely to move “angle of repose”

Which material would you expect to have the highest angle of repose? Sand grains B. glass beads C. marbles D: broken bricks E. dice

(3) Water

(4) Vegetation

(5) Loading

(6) Vibration Earthquakes Loud Noises Vehicles Machinery

(7) Size of Slope Bigger slopes less stable

(8) Underlying Structure

Wildfire in Santa Barbara Co, Calif. has burned 27,000 acres Wildfire in Santa Barbara Co, Calif. has burned 27,000 acres. In the next few years this area will experience higher mass wasting than previously. Why? Heat changed slope material Firefighters vibrated slope Water added to slope Slope has been loaded Vegetation removed

Types of Mass Wasting Creep

Slump

Slide – Landslide, rockslide

Flows – debris flow, mudflow, earthflow, avalanche

Rock Fall

SOLUTIONS Gabions

Fabric, mesh

Vegetation

Retaining Walls

Drainage

Recontouring

Diversion Structures

PRS Which prevention technique has the lowest initial cost? Gabions B. Diversion structures C. Recontouring D. Retaining Walls E. Vegetation

I - 40 What mistakes were made?

I – 40 Example

What’s wrong here?

Yungay, Peru May 31, 1970 50,000,000 m3 @ 200-400 km/hr killed 29,000

Yungay, Peru

Group Question What could have been done to prevent/minimize the damage?

Gros Ventre, Wyoming, 1925 37,000,000 m 50-80 mph dammed river

Group Question What could have been done to prevent/minimize the damage?