MASS WASTING

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´╗┐MASS WASTING

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SURFICIAL PROCESSES Erosion, Transportation, Deposition on the Earth's Surface Landscapes made and annihilated Involves air, water, gravity Agents: Mass squandering (gravity), Running water (streams), ice sheets (ice), wind, water waves, ground water

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MASS WASTING Masses of trash (mud, sand, rock) or bedrock moving downhill Landslides and slower developments Driven by GRAVITY

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Classification of Mass Wasting RATE of MOVEMENT Extremely moderate (~1mm/year) to exceptionally quick (>100 km/hour) MATERIAL Bedrock Debris-("soil", dregs)

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Classification of Mass Wasting TYPE OF MOVEMENT Flow Slide Translational slide Rotational slide (Slump) Fall

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Classification of Mass Wasting TYPE OF MOVEMENT Flow Slide Translational slide Rotational slide (Slump) Fall

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Controlling Factors Slope point tender versus soak Local alleviation low versus high Thickness of flotsam and jetsam over bedrock-slight versus awesome Planes of shortcoming ( in bedrock) bedding planes; foliation; joints planes at right edge to incline versus parallel to slant most risky

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Controlling Factors Climatic controls Ice-above solidifying versus solidify & defrost Water in soil-film around grain versus immersion Precipitation-visit however light versus times of dry season and overwhelming precipitation Vegetation-vigorously vegetated versus light or no vegetation Gravity Shear constrain parallel to slant, square's capacity to move Normal compel opposite to slant, piece's capacity to remain set up because of grating Shear quality imperviousness to development or misshapening of garbage

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The Effect of Slope & Gravity G=gravity S=shear F=friction N=normal F S G N

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Controlling Factors Water includes weight expanded pore weight in immersed garbage diminishes shear quality surface pressure in unsaturated trash builds shear quality Triggering Mechanisms Overloading Undercutting Earthquakes

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Common sorts of mass squandering CREEP delicate slants vegetation moderates development moderate stream (< 1 cm/year) encouraged by water in soil or by stop defrost in colder atmospheres Indicators of crawl 'gun handle' trees inclining gravestones, dividers, posts

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Solifluction & Permafrost Solifluction: Flow of water immersed trash over impermeable material Permafrost: Ground that remaining parts solidified for a long time

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Common sorts of mass squandering DEBRIS FLOW Motion occurring all through moving mass Includes Earthflow Mudflow Debris Avalanche

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Earthflow Primarily stream of flotsam and jetsam may include rotational sliding Scarp above Hummocky surface in lower part May be moderate or quick Solifluction part of Permafrost in chilly atmospheres

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Mudflow Flow of watery flotsam and jetsam Occurs where absence of vegetation: Dry atmospheres Volcanoes After woodland shoot

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Debris Avalanche Very fast, turbulent stream of garbage mud-stones >150 km/hr Triggered by volcanic emissions Mt. St. Helens 1980; Nevado del Ruiz 1985 serious rainstorms-Venezuela 1999 tremors Japan 2000

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Rockfalls and Rockslides Rockfall Bedrock loosening up on bluffs Talus at base of precipices Rockslide Bedrock included Sliding along planes of shortcoming parallel to slant Bedding planes; foliation planes; cracks in shake (joints)

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Debris Slides and Debris Falls Debris fall Free-falling mass of trash Debris slide Debris moving along an all around characterized surface

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The St. Francis Dam The dam stood 180 feet high and 600 feet since quite a while ago Curved Concrete Structure

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On March 12, 1928, after its store achieved full limit with respect to the first run through, the St. Francis Dam started to spill. At 11:57 PM, the dam caved in, sending 12 billion gallons of water seething through the thin San Francisquito Canyon into the Santa Clara Valley. Composed and fabricated two years before by William Mulholland to store water brought by the Los Angeles Aqueduct from Owens Valley. Its disappointment brought about a surge which slaughtered more than 450 individuals and wrecked structures, scaffolds, railways, and ranches. The St. Francis was stand out of 19 dams that Mulholland had built to store Los Angeles' water supplies.

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Preventing Landslides Preventing mass squandering of flotsam and jetsam Preventing rockfalls and rockslides on parkways

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L.A. Against the Mountains

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The 1934 surge calamity in Los Angeles bowl was horrific to the point that Woody Guthrie formed a melody called "Los Angeles New Year's Flood" to memorialize the hundred individuals who were covered alive, suffocated, or never found. Light rain started falling on December 30, 1933 , and quickly strengthened to a storm totaling 7.31 crawls in 24 hours. By midnight on December 31, 1934 , the San Gabriel Mountains, towering over the Los Angeles bowl, started to release gigantic flotsam and jetsam streams of mud, shakes and trees down many soak limit ravines. The trash streams achieved the bowl floor as 20-foot dividers of water, as they had accomplished for ages.

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The Geology of the Great Los Angeles Basin The Los Angeles bowl is a gathering of four alluvial fields named the San Gabriel Valley, Inland Valley, San Fernando Valley, and Coastal Plain. The fields are encompassed (pretty much) by three mountain ranges named the Santa Monica Mountains, the San Gabriel Mountains, and the Santa Ana Mountains. The San Gabriel is by a wide margin the best, with crests more than 10,000 feet, only 40 or 50 miles inland from the Pacific Ocean.

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The San Gabriel Mountains The San Gabriel Mountains orogeny crossed around 40 million years (25-65 million years prior) before quickening in the previous 1 million years. The San Gabriels are youthful mountains are as yet ascending as quickly as any mountain run on the planet. The San Gabriels ascended alongside a fabulous trough diving six miles underneath ocean level. Filled with shortcomings, the San Gabriels have since quite a while ago cracked effectively and disintegrated even with Pacific Ocean storms. The San Gabriels keep on disintegrating at one of the quickest rates on the planet, yet they are working up quicker than they are deteriorating.

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Debris Dam

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Fresh silt kept in flotsam and jetsam maintenance structure along the range front of the San Gabriel Mountains.

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Recent substantial avalanche covering street in the foothills of the San Gabriel Mountains

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Debris stream that started from vast avalanche over the town of La Conchita. Garbage stream source is from expansive 1995 avalanche. Little, late shallow avalanches in more seasoned scars from earlier years, east of I-5 in Orange County.

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