Climate (catch up)PowerPoint PresentationSlide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Mass WastingQuestionsWhat is Mass Wasting? (sometimes called landslides)Why is Mass Wasting an issue?Slide 30Slide 31Slide 32Influencing factorsSlide 34Slide 35Slide 361. Rock Fall (Rapid movement) material breaks free from a vertical wall or very steep slopeSlide 38Slide 392. SLIDES – (Rapid movement) a single, intact mass of rock, soil, or unconsolidated sediment becomes detached and moves rapidly downslopeSlide 41Slide 423. Slumps (Slow to Rapid movement)Slide 44Slide 454. Flows (Rapid movement)Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Earthflows – Quick claysSlide 57Slide 585. Creep (Slow movement)Slide 60Slide 61Slide 626. Solifluction (Slow movement)Slide 64Slide 65Slide 667. Complex movementsSlide 68Causes and triggers of mass movementSlide 70Slide 71Other means to prevent mass wastingSlide 73Slide 74Slide 75Climate (catch up)Why focus on Carbon?Gas content of a magma:Water vaporCarbon dioxideCarbon monoxideNitrogenSulfur dioxideHydrogen sulfideChlorineCO2 Concentrations Over the Past 400,000 YearsWhy focus on Carbon?Humans release about 26GT of carbon each year;Volcanoes release about .3 GTChemical and Physical Laws•Ideal Gas LawPV = nRT•P = Pressure•V = Volume occupied•N = Avagadro’s number (constant)•R = Ideal gas constant•T = Temperature•If P increases, what MUST happen?Why focus on Carbon?Carbon is a very reactive elementReduced C4-Oxidized C4+Carbon•Carbon can form various ions•C4+ Oxidized carbon (inorganic)Ex) C4+ + 2O2- = CO2•C4- Reduced Carbon (Organic)C4- + 4H+ = CH4Photosynthesis:Takes Oxidized Carbon and Reduces itReduced Carbon has more electrons, thus more potential energyEarly earth – a reducing atmosphere•Methane rich•Little Free O2•An aside: oxygen is toxic to cellsPhotosynthesis - cyanobacteriaFossils from 3.5 bya:StromatolitesPhysical evidence from sedimentIron •Fe 2+ (reduced)•Fe 3+ (oxidized)•Oxidized Iron is Red•Reduced Iron is DarkBanded Iron FormationsAfter ~ 2.0 bya, Banded Iron deposition ceasesOnly Red Beds remainGlaciationHelps understandFaint Young SunCoalThe CarboniferousBiota and atmosphere from 65 mya to presentMass WastingMass WastingLecture 27Lecture 27Questions•How are mass movements classified and recognized?•What are the causes of mass movements?•What are the risk factors for mass movements?•How can mass wasting events be prevented?What is Mass Wasting?(sometimes called landslides)•“Downhill movement of rock, soil and/or other debris under the influence of gravity”•Often initiated by other factors•Mass Wasting can be Fast or Slow•Can involve all geologic materials•Usually associated with steep terrains, but can occur elsewhereWhy is Mass Wasting an issue?•Each year, in the US alone, some $1-2 Billion in damages occur from mass wasting and, on average 25 lives are lost•World wide, there have been numerous deaths, injuries and damages•Geologically, Mass Wasting is a critical PROCESS of exposure and break-down of rock and sediment•Results in an ever-changing landscapeUS 441 in GSMNP. January 2013Landslide at mile marker 2.6 on Interstate 40 in North Carolina, Oct. 25, 2009Influencing factors–Type of material•Consolidated v. Unconsolidated•Geologic Structures•Bedding and/or dip–Water – adds mass; decreases friction–Vegetation – adds mass, but binds sediment, removes water–Climate – high precipitation = greater risks–Construction – disturbs slope stability–Elevation/Latitude – climate, –Overloading (adding mass) – construction of structures, roads, etc.Influencing factorsImpact of Human Activities•Increasing angle of slopes•Removal of vegetation•Added mass of building on slopes•Addition/removal of waterTypes of Mass Movement•Includes all types of slope failures•Classified by–Type of material–Type of motion–Rate of movement1. Rock Fall (Rapid movementRapid movement)material breaks free from a vertical wall or very steep slopeTALUSVery rapid movements; Talus builds up at base of slopes2. SLIDES – (Rapid movementRapid movement) a single, intact mass of rock, soil, or unconsolidated sediment becomes detached and moves rapidly downslopeMaterial moves down The Dip of the rocksRock Slide along I-40In the Pigeon River GorgeNear NC/TN borderDip of rocks is the slide plane3. Slumps (Slow toSlow to Rapid movementRapid movement)a downward and outwardmovement of an Intact Mass of unconsolidated materialalong a curved surfaceSmall slump along a road bedLarge slump in CaliforniaWith Debris flow4. Flows (Rapid movementRapid movement)•a mixture of mostly unconsolidatedunconsolidated particles that moves downslope like a viscous fluid•Materials behave as a fluid•Several subcategories:•Mudflows (lahars); Earthflows•DEBRIS FLOWSDEBRIS FLOWS: a slurry of water and particles larger than mud. Can include vegetation, structures as well as geologic materialMudflows•Debris flows consisting of silt and clay sized particles–Usually associated with heavy rain–High water content - up to 30%–Usually follow stream valleysLahars•Volcanic debris flows–Common is loose pyroclastic material–Rain or melting snow saturates soil and rock–Explosive eruptions and associated earthquakes can be triggers–Very fast flowing - up to 150 km/hrMt. St. Helens - laharDebris Flows•Mixtures of water, mud and rock–Liquified soil flows downhill•Up to 50 km/hr–Water lubricates mass of soil and rock–Large boulders, buildings etc. may be carried by viscous fluidEarthflows – Quick clays•Problem in high latitude regions•Clays can become mobilized and flow•Generally susceptible during earthquakes and other seismic events1964 Alaskan earthquake5. Creep (Slow movementSlow movement)•Very common form of mass wasting•Extremely slow movement of soil and regolith - 1 to 10 mm/yr•Combination of factors cause creep–Heaving of soil - expansion & contraction is the primary cause•Wet-dry cycles•Freeze-thaw cycles6. Solifluction (Slow movementSlow movement)•Creep that occurs in permafrost–Melting of soil water occurs from the surface down–Permafrost prevents downward percolation–Surface soils become saturated and begin to flow–Also can “pluck” and move cobble7. Complex