Exam 2 Review

Exam 2 Review - Study Exam 2 Work of Gravity in mass...

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Study Exam 2 Work of Gravity in mass wasting o For rocks, sediments soils, everything on a slope! o Pulls everything towards the center of the earth o When on a slope the force of gravity is resolved into two components, one perpendicular to the slope and one downward o Gravity and Erosion cause all mass wasting As long as there is a slow there is mass wasting = no minimum slope Angle of Repose o Differs for various materials. o Angle that each material can withhold before being pulled down by gravity. Sand – high Cement - low o If gravity is stronger than the forces holding an object on the slope, then the object will move down a slope Mass Wasting o Downslope movement of material under the influence of gravity o Material: rock, regolith (rock and soil) and soil o Mass wasting and erosional processes slowly lower and flatten the land surface o Combined effects of mass wasting and running water produce stream valleys o No minimum angle is required for mass wasting to occur. o Most rapid and spectacular mass-wasting events occur in areas of rugged, geologically young mountains. Controls and Triggers of Mass Wasting: o Water o Diminishes particle cohesion (friction) Angle of repose decreases drastically o Adds weight o Oversteepening of slopes—slope angle o Causes unstable slopes o When roads are carved into the sides of mountains and the mountain slope becomes too steep it is unstable and often falls onto the road o Removal of Vegetation o Vegetation roots make slopes more stable o Earthquakes o Cause liquefaction – water-saturated surface materials behave as fluid-like masses that flow Mass Wasting features o Source area – where the material leaves o 1. Head scarp – where mass area leaves, vertical land remaining o 2. Main body – middle area
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o 3. Deposition area (toe) – where the material is accumulated Classification of Mass Wasting Processes o Type of material o Mud, Earth, Rock o Type of motion o Fall Drop in material, sharp vertical edges left o Flow (chaotic mixture with water: e.g. mudlfow) o Slump (along a curved surface) Various smaller pieces of land slumping down, like stairs o Slide (along a flat surface) Large area of land slide down a slope o Velocity of the movement o Fast o Slow Creep - Gradual movement of soil and regolith downhill, aided by the alternate expansion and contraction of the surface material When fences and tree trunks are bent Downslope Solifluction – at high latitudes Caused by freezing and melting of ice and land Interferes with Alaskan railroads Permafrost Q = Identify Head scarp, main body, toe Which of the four factors are a part of a specific mass wasting
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Visible effects of mass wasting? Review and analyze images!!! o
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This note was uploaded on 03/05/2011 for the course GEOL 101 taught by Professor All during the Fall '08 term at George Mason.

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Exam 2 Review - Study Exam 2 Work of Gravity in mass...

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