Term
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Definition
| downslope movement of earth's materials |
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Term
| the term landslides sometimes includes |
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Definition
| debris flow, rock falls, and avalanches |
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Term
| The most common landform on the erath |
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Definition
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Term
| Where are free face slopes more common? |
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Definition
| On strong rocks or in arid environments. |
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Term
| Describe a free face slope. |
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Definition
| A high cliff of hard rock that forms a straight, nearly vertical slope segment. |
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Term
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Definition
| Rock fall that accumulates at the base of a cliff or slope |
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Term
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Definition
Falling
Sliding
Slumping
Flowage/flow
Creep |
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Term
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Definition
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Term
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Definition
| downslope movement of a coherent block of earthmaterial along a planar slip plane |
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Term
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Definition
| Sliding along a curved slip plane producing slump blocks. |
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Term
| Flowage or flow landslide |
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Definition
| Downslope movement of unconsolidated material in which particles move about and mix within the mass |
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Term
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Definition
| Very slow flowage. Progressively tilts telephone poles, fences and tree trunks. Trees grow faster than creep moves, so tress are crooked. |
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Term
| Four variables in downslope movement |
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Definition
| 1- The mechanism of the movement (slide, fall, flow or complex movement) 2- Type of earth material (solid rock, soft consolidated sediment or loose material) 3- Amount of water present 4- Rate of movement |
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Term
| Forces that influence slope stability |
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Definition
Driving forces
Resisting forces
Shear strength |
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Term
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Definition
| Move earth materials down a slope |
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Term
| Resisting forces on slopes |
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Definition
| Oppose the downward driving forces |
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Term
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Definition
| The most common resisting force. Resists by sliding or flowing along potential slip lines |
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Term
| Slope stability is evaluated by... |
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Definition
| calculating the Safety Factor. |
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Term
| How to calculate safety factor |
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Definition
| The ratio of the resisting forces to the driving forces. Greater than 1 is stable, the resisting forces exceed the driving forces. Less than 1 - slope failure can be expected b/c driving forces exceed the resisting forces. |
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Term
| The shape of the slip surface in slides is strongly conrolled by the type of __________________. |
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Definition
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Term
| Slides have two basic patterns of movement. |
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Definition
Rotational, with curved slip surfaces
and
Translational, planar slip surfaces |
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Term
| Slumps are most common in |
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Definition
| unconsolidated earth material and in mudstone, shale and other weak rocks. |
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Term
| Movement in translational slides |
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Definition
| moves along inclined slip planes within and parallel to a slope. |
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Term
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Definition
| thick mixtures of mud, debris, and water. |
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Term
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Definition
| The angle at which snow, or any loose material, is stable. Generally, stable at less than 25 degrees. |
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Term
| Two types of snow avalanches |
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Definition
| Loose-snow avalanches - starts at a point and widens as it moves downslope Slab avalanches - start has cohesive blocks of snow and ice that move downslope. |
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Term
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Definition
| Tracks produced by previous avalanches that future avalanches will usually follow |
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Term
| Three factors that will increase world-wide landslide activity. |
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Definition
Development in landslide prone areas
Treecutting in landslide prone areas
Changing global climate patterns will produce regional increases in precipitation |
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Term
| Direct effects of landslides |
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Definition
-Injury from falling debris
-damaged homes
-blocked roads and railroads |
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Term
| Indirect effects of landslides |
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Definition
-upstream flooding
-transmission of disease |
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