29 terms

Edward A. Keller Intro to Environmental Geology Chapter Ten: Slope Processes and Types of Landslides

mass wasting
a comprehensive term for any type of downslope movement of Earth materials
earthflows and mudflows, rock-falls, and snow or debris avalanches
the very slow to rapid sinking or settling of Earth materials
a straight, nearly verticle slope segment (like El Capitan)
talus slope
fragments that fall from the free-face may accumulate at the base of the slope and for this
often originates ona slope where soil partially liquefies and runs out
also known as a debris flow, a mixture of rock, soil, and organic matter that mixes with air and water to flow rapidly down slope
debris avalanche
a very rapid to extremely rapid debris flow
lateral spreads
a type of landslide that often occurs on nearly flat slopes or very gentle slopes
driving forces
move Earth materials down a slope
resisting forces
oppose driving forces
slip planes
are geologic survaces exhibiting weakness in the slope material
factor of safety
defined as the ratio of the resisting forces to the driving forces
rotational slides
also known as slumps, the sliding occurs along a curved slip surface and tends to produce topographic benches that can be rotated and tilted int he upslope direction, common on soil slopes but can occur on some rock slopes, like shale
transitional slides
planar (occur along an inclined slip plane within a slope), common on rock slopes
soil slips
a type of transitional slide, are very shallow slides in soil over rock that occur to the slope
a mixture of weathered rock and other material
the very slow downslope movement of soil or rock
how steep a hill slope is
the characteristic weather at a particular place or region over seasons, years, or decades
quick clay
spontaneous liquefaction of clay-rich sediments, often produces slides
unstratified material
drainage control
surface and subsurface drainage control used to stabilize a slope.
changing the ground level to a smooth horizontal or gently sloping surface
slope supports
used to hold back excavation on restricted sites, and is capable of resisting the pressures of earth and groundwater
snow avalanche
a rapid downslope movement of snow and ice, sometimes with the addition of rock, soil, and trees
tracks previousl produced by other avalanches
a circular area of subsidence caused by the collapse of near-surface suberranean void or room in a cavern