PEO 3 - Mass Wasting Flashcards
What is mass wasting?
Erosion (movement) of material primarily by gravity (through small amounts of water often facilitate movement)
Define creep.
The slowest of the wasting types.
Rippled.
The whole landscape is sliding downhill, slowly all of the time.
Expansion caused by freezing leads to contraction during thawing which slowly causes it to creep downhill.
Define slump.
Slightly faster than creep.
Material moves slowly to create a slump of settlement.
Usually caused by a heavier rain or earthquake.
Tends to leave a scar.
Often the steeper part of a slope.
Can sometimes be very large.
Define solifluction.
Looks as if the land is melting one way.
Unique to areas that freeze and thaw.
Define earth flow.
Looks sort of like oozing.
Define rock fall.
A pile of rocks and debris that have fallen from a steep face.
The event is quick and can be large, but the overall even is a very slow process.
Define Rock avalanche.
This is fast.
Happens in one event.
Happens where there are glaciers that can melt quickly and combine with the soil and dirt in the area that can flow downward.
Catastrophic.
Affects the entire landscape, not just one area.
Define rock slide.
Happens when there is a layer of rock that has been broken up by frost wedging. When rain or water gets in the crevices they can be pushed forward (such as by rain) and it causes the rocks to fall.
It is one particular layer that is let go and slides downward.
Often overlies a muddy layer.
Gets broken up by mechanical weathering enough to where the rock is broken and it can become a lubricant. Often happens that something breaks off at the bottom and it continues upward with more and more breaking.
Define landslide.
The entire territory moves including everything on it (vegetation, houses, etc.).
Typically triggered the same way as a rock slide by having some lubricant, like a clay bed, underneath, and causing the slide.
Can be devastating if you are on the piece that moves or if you live downslope from the piece that moves.
Define mudflow.
The most dangerous, most devastating type of mass wasting.
It is like a water flood, but with mud and rocks and sorts.
It is called debris flow in addition to mud, there is rocky stuff.
A mudflow looks like it is a river, but it is not the water that is moving it, the water is only making it movable, so it is much more powerful and dangerous than a water flow.
Lahar.
