PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6classification of mass wastingSlide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34summary: rates and types of mass wastingcontrolling factors in mass wastingSlide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47improve drainage -- leads to less creepmodify slopes (where layering dips into roadway)QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.mass wastingQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.11:37 am on August 17, 1959magnitude 7.1? earthquake West Yellowstone, Montanatriggered landslide of85 million tons of rocksped downslope at 150 km/hrandproduced hurricane force winds• cars blown into air• valley floor covered by 45 m of rubble• 28 people (campers) were killedproduced waves in Hebgen Lakethat swept over damMadison Canyon slideQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.mass movements occur everywhere……estimate damage annually in US at $1.5 billion… …less than 1,000 deaths of 20,000 lost in natural disastersfrom 1925-1975 were from mass movements not likely to be killed by mass movements, but likely to pay for effectsQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.classification of mass wastingrate of movementtype of materialtype of movementcm/year to 100 km/hoursolid bedrock or unconsolidated debrisflow, slide, fall, creepflow: viscous fluidslide: mass remains intact (2 types: landslide; slump)fall: free-fall of materialtypes of movementQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.fastestrock fallQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.rock fall in actionrock fall with talus slopeQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.hill gives way in coherent mass --large block movesQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.surface of movementisconcavescarp(type of slide but with rotation)QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.submarine landslides (Hawaii)QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.landslides on MarsQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.move slowly (viscous)1-2 meter/hourflows: earthflowsolifluctionQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.earth flowsandsolifluctionQuickTime™ and aSorenson Video decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.may move quickly overgentle slopes(1°-2°)flows: mud flow (mixture of debris and water)mud flow at Nevada Huascaran, Peru: killed 18,000 peoplebeforeafterdried mudflowmudflow on Toutle River from Mt. St. HelensQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.flows: soil creepdownslope motion for creepfreeze/thaw cycleQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.permafrost: another example of freeze/thawQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.summary: rates and types of mass wastingcontrolling factors in mass wasting•gravity (friction and slope angle)• slope composition• vegetation• water• large reliefgravity: 2 factors in balance1) gravity--pulls object to center of Earth2) friction--resists block sliding downslope• component perpendicular (normal) to surface(contributes to friction)• component parallel (shear) to surface(contributes to sliding)• depends on angle of slope; slipperiness of slope; and magnitude of normal component of gravityrelief: change in elevationgreater difference in relief yields greater shear forcesalong slopes1) small amounts of water2) excessive amounts of waterQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.water: two effects• counteracts normal component of gravity…water pushed upward…• reduces friction between surface material and underlying rock• glues particles by surface tension--”sand castles”slope composition (amount of loose rock)….solid bedrock, unconsolidated bedrock (loose or weathered material)solid rockvery stable even as cliffs…NOT stable if:• has lots of fractures (cracks)• is soluble (limestone) such that cavities form• has layering of “wrong” orientation …bedding (sedimentary rocks) or foliation (metamorphic rocks)effect of bedding planes in sedimentary rocklet’s be smart…recognize and preventslope composition (continued)….solid bedrock, unconsolidated bedrock (loose or weathered material)unconsolidated materialstability depends on frictional properties…• is stable until maximum angle…angle of repose…• is highly dependent on water contentQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.angle of repose: maximum angle where friction balances gravityroots stabilize loose, unconsolidated material…removal (by fire or clear-cutting) leads to mass movementvegetationQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.preventionwater, weight of house, road cutimprove drainage -- leads to less creepmodify slopes (where layering dips into