Mass wasting - wikipedia Mass wasting This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please help to improve this article by introducing more precise citations. ( December 2015 ) Talus cones produced by mass wasting, north shore of Isfjord, Svalbard, Norway. Mass wasting at Palo Duro Canyon, West Texas ( 2002 ) A rockfall in Grand Canyon National Park Mass wasting, also known as slope movement or mass movement, is the geomorphic process by which soil, sand, regolith, and rock move downslope typically as a solid, continuous or discontinuous mass, largely under the force of gravity, but frequently with characteristics of a flow as in debris flows and mudflows. Types of mass wasting include creep, slides, flows, topples, and falls, each with its own characteristic features, and taking place over timescales from seconds to hundreds of years. Mass wasting occurs on both terrestrial and submarine slopes, and has been observed on Earth, Mars, Venus, and Jupiter 's moon Io. When the gravitational force acting on a slope exceeds its resisting force, slope failure ( mass wasting ) occurs. The slope material 's strength and cohesion and the amount of internal friction between material help maintain the slope 's stability and are known collectively as the slope 's shear strength. The steepest angle that a cohesionless slope can maintain without losing its stability is known as its angle of repose. When a slope made of loose material possesses this angle, its shear strength perfectly counterbalances the force of gravity acting upon it. Mass wasting may occur at a very slow rate, particularly in areas that are very dry or those areas that receive sufficient rainfall such that vegetation has stabilized the surface. It may also occur at very high speed, such as in rockslides or landslides, with disastrous consequences, both immediate and delayed, e.g., resulting from the formation of landslide dams. Factors that change the potential of mass wasting include : change in slope angle, weakening of material by weathering, increased water content ; changes in vegetation cover, and overloading. Volcano flanks can become over-steep resulting in instability and mass wasting. This is now a recognised part of the growth of all active volcanoes. It is seen on submarine as well as surface volcanoes : Loihi in the Hawaiian volcanic chain and Kick ' em Jenny in the Caribbean volcanic arc are two submarine volcanoes that are known to undergo mass wasting. The failure of the northern flank of Mount St Helens in 1980 showed how rapidly volcanic flanks can deform and fail. Contents 1 The importance of water in mass wasting 2 Types of mass wasting 2.1 Creeps 2.2 Landslides 3 Triggers of mass wasting 4 Reducing the impacts of mass wasting 5 See also 6 References 7 External links The importance of water in mass wasting Water can increase or decrease the stability of a slope depending on the amount present. Small amounts of water can strengthen soils because the surface tension of water increases soil cohesion. This allows the soil to resist erosion better than if it were dry. If too much water is present the water may act to increase the pore pressure, reducing friction, and accelerating the erosion process and resulting in different types of mass wasting ( i.e. mudflows, landslides, etc. ). A good example of this is to think of a sand castle. Water must be mixed with sand in order for the castle to keep its shape. If too much water is added the sand washes away, if not enough water is added the sand falls and can not keep its shape. Water also increases the mass of the soil, this is important because an increase in mass means that there will be an increase in velocity if mass wasting is triggered. Saturated water, however, eases the process of mass wasting in that the rock and soil debris are easily washed down - slope. Types of mass wasting Based on how the soil, regolith or rock moves downslope as a whole, mass movements can be broadly classified as creeps and landslides. Creeps Soil creep is a slow and long term mass movement. The combination of small movements of soil or rock in different directions over time are directed by gravity gradually downslope. The steeper the slope, the faster the creep. The creep makes trees and shrubs curve to maintain their perpendicularity, and they can trigger landslides if they lose their root footing. The surface soil can migrate under the influence of cycles of freezing and thawing, or hot and cold temperatures, inching its way towards the bottom of the slope forming terracettes. Landslides A landslide, also called a landslip, is a slow or rapid movement of a large mass of earth and rocks down a hill or a mountainside. Little or no flowage of the materials occurs on a given slope until heavy rain and resultant lubrication by the same rainwater facilitate the movement of the materials, causing a landslide to occur. In particular, if the main feature of the movement is a slide along a planar or curved surface, the landslide is termed slump, earth slide, debris slide or rock slide, depending on the prevailing material. Movement of soil and regolith that more resembles fluid behavior is called a flow. These include avalanches, mudflows, debris flows, earth flow, lahars and sturzstroms. Water, air and ice are often involved in enabling fluid - like motion of the material. A fall, including rockfall and debris fall, occurs where regolith cascades down a slope, but is not of sufficient volume or viscosity to behave as a flow. Falls are promoted in rocks which are characterized by the presence of vertical cracks. Falls can also result from undercutting by running water as well as by waves. They usually occur at very steep slopes such as a cliff face. The rock material may be loosened by earthquakes, rain, plant - root wedging, and expanding ice, among other things. The accumulation of rock material that has fallen and resides at the base of the structure is known as talus. Triggers of mass wasting Soil and regolith remain on a hillslope only while the gravitational forces are unable to overcome the frictional forces keeping the material in place ( see slope stability ). Some factors that reduce the frictional resistance relative to the downslope forces, and thus can trigger slope movement, can include : earthquakes increased overburden from structures increased soil moisture reduction of roots holding the soil to bedrock undercutting of the slope by excavation or erosion weathering by frost heave or chemical dissolution bioturbation Reducing the impacts of mass wasting Afforestation Re-Afforestation Terracing steps on slopes or, more generally, re-modeling its shape Slope stabilization See also SMR classification References Jump up ^ Britannica Monroe, Wicander ( 2005 ). The Changing Earth : Exploring Geology and Evolution. Thomson Brooks / Cole. ISBN 0 - 495 - 01020 - 0. Selby, M.J. ( 1993 ). Hillslope Materials and Processes, 2e. Oxford University Press. ISBN 0 - 19 - 874183 - 9. Fundamentals Of Physical Geography ( Class 11 NCERT ). ISBN 81 - 7450 - 518 - 0 External links Wikimedia Commons has media related to mass movements. Georgia Perimeter College : Mass Wasting CSU Long Beach : Introduction to Mass Wasting WFPA : Geology, Topography, Storms and Landslides in Washington State Geotechnical engineering Exploration Investigation Testing On - site Cone penetration test Standard penetration test Monitoring well piezometer Borehole Crosshole sonic logging Nuclear densometer test Static load testing Laboratory Atterberg limits California bearing ratio Direct shear test Hydrometer Proctor compaction test R - value Sieve analysis Triaxial shear test Hydraulic conductivity tests Water content tests Soil Materials Clay Silt Sand Gravel Peat Permafrost Loam Loess Properties Soil classification Hydraulic conductivity Water content Void ratio Bulk density Thixotropy Reynolds ' dilatancy Angle of repose Cohesion Porosity Permeability Specific storage Mechanics Effective stress Pore water pressure Shear strength Overburden pressure Consolidation Compaction Shear wave Lateral earth pressure Foundations Shallow Deep Bearing capacity Dynamic load testing Pile integrity test Wave equation analysis Statnamic load test Retaining walls Gabion Ground freezing Mechanically stabilized earth Pressure grouting Slurry wall Soil nailing Tieback Stability Slope analysis mass wasting landslide Deformation monitoring automated Earthquakes Soil liquefaction Response spectrum Seismic hazard Ground -- structure interaction Geosynthetics Geotextile Geomembrane Geosynthetic clay liner Cellular confinement Numerical analysis SEEP2D STABL SVFlux SVSlope UTEXAS Geologic principles and processes Stratigraphic principles Principle of original horizontality Law of superposition Principle of lateral continuity Principle of cross-cutting relationships Principle of faunal succession Principle of inclusions and components Walther 's law Petrologic principles Intrusive Extrusive Volcanic Exfoliation Weathering Pedogenesis Diagenesis Compaction Metamorphism Geomorphologic processes Plate tectonics Salt tectonics Tectonic uplift Subsidence Marine transgression Marine regression Sediment transport Fluvial processes Aeolian processes Glacial processes Mass wasting processes Natural disasters Geological Earthquakes Mass wasting Landslides Mudflows Lahars Ice calving Volcano eruption Avalanches Sinkholes Quicksands Water Flood Coastal flood Flash flood Storm surge Limnic eruption Tsunami Cloudburst Meteotsunami Weather Ice Cold wave Winter storm Thundersnow Ice storm Blizzard Ground blizzard Snowsquall Hail Freezing rain Whiteout ( weather ) Black ice Cryoseism Freezing drizzle Ice jacking Ice jam Jumble ice Heat Droughts Heat waves Heat burst Backdraft Megadrought Torridness Wind Storms Storm surge Dust storm Thunderstorm Severe thunderstorm Supercell Firestorm Gale Sirocco Simoon Haboob Cyclone Mesocyclone Tropical cyclones Extratropical cyclone Subtropical cyclone European windstorm Derechos Atlantic hurricane Typhoon Downdraft Tornado Multiple - vortex tornado Landspout Waterspout Fire whirl Gustnado Dust devil Whirlwind Lightning strike Air - mass thunderstorm Hypercane Microburst Monsoon Fire Wildfires Firestorm Fire whirl Health Outbreak Epidemic Pandemic Famine Space Gamma - ray burst Fast radio burst Cosmic rays ( Ultra-high - energy cosmic ray ) Impact event Meteor shower Particle shower Solar proton event Solar flare Coronal mass ejection Astrophysical jet Tidal disruption event Geomagnetic storm Gravitational collapse Kilonova Nova Supernova impostor Pair - instability supernova Supernova Hypernova Quark - nova Stellar collision Galactic collision Galactic merger Heat death of the universe Big Rip Big Crunch False vacuum metastability event Retrieved from `` https://en.wikipedia.org/w/index.php?title=Mass_wasting&oldid=848972093 '' Categories : Environmental soil science Geological hazards Geomorphology Hidden categories : Articles lacking in - text citations from December 2015 All articles lacking in - text citations Commons category with local link different than on Wikidata Talk Contents About Wikipedia Cymraeg Deutsch Español Esperanto فارسی Français Bahasa Indonesia עברית Nederlands Norsk Polski Svenska 中文 4 more Edit links This page was last edited on 5 July 2018, at 16 : 08 ( UTC ). 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Question: where is mass wasting most likely to occur
Answer: on a slope