Mass WastingMass Wasting Mass WastingImportant triggering factorsImportant triggering factorsImportant triggering factorsImportant triggering factorsMass Wasting Types of mass wasting processesTypes of mass wasting processesTypes of mass wasting processesForms of mass wasting Types of mass wastingUSGS Landslide TypesForms of mass wastingSlump—diagram SlumpGovernment Hill, AKGovernment Hill, AK seismic cross sectionForms of mass wasting Rockslide—diagramElkton, Oregon, March 4, 2006Elkton, Oregon, March 4, 2006Nevado HuascaránGros Ventre rockslide--diagramGros Ventre landslide—photoSlide Lake, WyomingSherman Glacier Rock Avalanche, March 1964 Rock FallRock FallForms of mass wastingSnohomish County, WA January 2006US 50, Sierra Nevadas, California 1997La Conchita, CaliforniaLa Conchita, CaliforniaLa Conchita, 2005Slide Mountain, Nevada, 1983Debris flow damageLahar debris flowToutle River Debris FlowNevado del RuizEruption of Nevado del RuizConfluence of lahars, Nevado del RuizArmero site, Nevado del RuizPhilippine Landslide, 2006Scar of Philippine landslideForms of mass wastingEarthflow—diagramHollywood Hills, CANiigata, Japan, 1964Anchorage, AK1964 liquefaction damageAlaska, 1964Sheffield Dam, 1925Forms of mass wastingCause of creep—frost heave Some visible effects of creepCreepCreepForms of mass wastingSolifluction LobesGround subsidence in Alaska due to solifluctionMeasuring ground movementMass Wasting PotentialMass Wasting PotentialMass WastingMass WastingMass Wasting The downslope movement of rock, regolith, and soil under the direct influence of gravity Gravity is the controlling forceMass WastingImportant triggering factors• Saturation• Oversteepening• Removal of vegetation • Ground vibrationsImportant triggering factorsSaturation of the material with water• Destroys particle cohesion• Water adds weightImportant triggering factorsOversteepened slopes • Unconsolidated granular particles assume a stable slope called the angle of repose• Stable slope angle is different for various materials • Oversteepened slopes are unstableImportant triggering factorsOversteepened slopes • Undercutting by streams• Undercutting by human interference• Addition of material to top of slope• Natural—deposition• Human-caused--constructionImportant triggering factors• Removal of anchoring vegetation• Wildfires• Drought• Development, logging • Ground vibrations • from earthquakesMass Wasting Types of mass wasting processes Defined by • The material involved • The movement of the materialTypes of mass wasting processesDefined by the material involved • Debris•Mud•Earth•RockTypes of mass wasting processesDefined by the movement of the materialThe character of the movement • Fall• Slide• FlowTypes of mass wasting processesDefined by the movement of the material The rate of the movement •Fast•SlowForms of mass wasting •Slump• Rockslide• Debris flow• Earth flow• Creep• SolifluctionTypes of mass wastingUSGS Landslide Types• http://pubs.usgs.gov/fs/2004/3072/fs-2004-3072.htmlForms of mass wastingSlump• Rapid movement along a curved surface• Occur along oversteepened slopesSlump—diagramSlump• http://www.physicalgeography.net/fundamentals/10x.htmlGovernment Hill, AK• 1964• http://walrus.wr.usgs.gov/geotech/radaraapg/fig4.htmlGovernment Hill, AK seismic cross section• http://walrus.wr.usgs.gov/geotech/radaraapg/fig5.htmlForms of mass wastingRockslide • Rapid • Blocks of bedrock move down a slopeCousin to RockfallRockslide—diagram• http://www.kmtr.com/mediacenter/[email protected],[email protected],[email protected],[email protected],[email protected]&navCatId=5&2=2Elkton, Oregon, March 4, 2006• http://www.kmtr.com/news/local/story.aspx?content_id=010798AE-AF2F-41D5-93F5-120A64493D45Elkton, Oregon, March 4, 2006• http://www.kmtr.com/news/local/story.aspx?content_id=010798AE-AF2F-41D5-93F5-120A64493D45NevadoHuascarán• Peru 1970• Buried two towns• 18,000 killed• Geologists warned government of potentialhttp://landslides.usgs.gov/html_files/landslides/slides/slide5.htmGros Ventre rockslide--diagramGros Ventrelandslide—photo• http://www.goldengatephoto.com/WestUS/wyother.html#grosventreSlide Lake, Wyoming• http://www.uwsp.edu/geo/projects/geoweb/participants/dutch/VTrips/GrosVentre.HTMSherman Glacier Rock Avalanche, March 1964Rock Fall• July 1996• Yosemite• http://landslides.usgs.gov/html_files/landslides/slides/slide9.htmRock Fall• http://sts.gsc.nrcan.gc.ca/geoscape/vancouver/graphics/mountain1.gifForms of mass wastingDebris flow (mudflow) • Rapid flow of debris with water• Confined to channels • Dry areas with heavy rains • Lahar composed of volcanic materialsSnohomish County, WAJanuary 2006• http://www.komotv.com/stories/41527.htmUS 50, Sierra Nevadas, California1997http://landslides.usgs.gov/monitoring/hwy50/index.phpLa Conchita, California• Spring 1995• No one injured or killed• http://landslides.usgs.gov/html_files/landslides/slides/slide21.htmLa Conchita, California• February 2005La Conchita, 2005• http://www.redcross.org/article/0,1072,0_312_3943,00.htmlSlide Mountain, Nevada, 1983http://landslides.usgs.gov/html_files/landslides/slides/slide2.htmDebris flow damageLahar debris flow• http://landslides.usgs.gov/html_files/landslides/slides/slide13.htmToutle River Debris Flow• http://pubs.usgs.gov/fs/fs-176-97/fs-176-97.htmlNevado del Ruiz• http://volcanoes.usgs.gov/Hazards/What/Lahars/RuizLahars.htmlEruption of Nevado del Ruiz• http://volcanoes.usgs.gov/Hazards/What/Lahars/RuizLahars.htmlConfluence of lahars, Nevado del Ruiz• http://volcanoes.usgs.gov/Hazards/What/Lahars/RuizLahars.htmlArmero site, Nevado del Ruiz• http://volcanoes.usgs.gov/Hazards/What/Lahars/RuizLahars.htmlPhilippine Landslide, 2006• http://www.alertnet.org/thenews/pictures/MAN52D.htmScar of Philippine landslide• http://news.yahoo.com/news?tmpl=story&u=/060219/481/xbm10202190643Forms of mass wastingEarthflow• Rapid or slow• Typically occur on hillsides in humid regions • Water saturates the soil • Liquefaction: associated with earthquakes and clay soilsEarthflow—diagramHollywood Hills, CA• January 2005• http://www.cnn.com/interactive/weather/0501/gallery.storms/frameset.exclude.htmlNiigata, Japan, 1964• http://www.ce.washington.edu/~liquefaction/selectpiclique/nigata64/tiltedbuilding.jpgAnchorage, AK1964•
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