chapter 11 (3)

Question 1

What is the main driving force for mass wasting?

Answer 1

Gravity

Question 2

Slope steepness

Answer 2

the influence of gravity is greater on steeper slopes versus gentle slopes.

Question 3

What are the “head” “toe” and “scarp” of a landslide?

Answer 3

head- beginning
toe-end
scarp- shelf created by sliding land

Question 4

Slope Materials

Answer 4

-Slopes made of loose material are less stable.
-Slopes made of solid material is more stable

Question 5

Water content

Answer 5

-A little bit of water can make a slope more stable
-Too much water can greatly decrease the slope’s stability

Question 6

Vegetation

Answer 6

-roots help to stabilize the land by strengthening the unconsolidated soil, sediment, and other slope
material

Question 7

What physical weathering process often triggers rock falls?

Answer 7

Freeze thaw cycles

Question 8

Falls

Answer 8

-the fastest form of mass wasting
-Material free falls of rolls down a steep slope or cliff
-Many cliffs along mountain highways are undercut
-caused by freeze-thaw cycles

Question 9

Slides that occur along a single planar surface of failure

Answer 9

translational slide

Question 10

Slides that occur on multiple curved slip surfaces

Answer 10

slump

Question 11

Flows

Answer 11

-occur when unconsolidated slope material becomes water saturated

-triggerd by rain / snowfall

Question 12

Creep

Answer 12

very slow type of earthflow, moving as slow as 1mm per year.

Question 13

Subsidence

Answer 13

-The gradual settling or sudden collapse of relatively stable land
-caused by the compaction of underlying rocks, particularly porous and/or water-saturated rocks
-caused when humans draw out water from aquifers, or petroleum

Question 14

Sinkholes

Answer 14

-develop where the bedrock is composed of limestone
-limestone dissolves to form caverns underground
-Caverns that form close to the surface may collapse in on themselves and create sinkholes
-also cause by humans mining

Question 15

Weather
(cause of land failure)

Answer 15

-can trigger mudflows, debris flows, and lahars
-Freeze thaw cycles can trigger rock falls

Question 16

Earthquakes
(cause of land failure)

Answer 16

can shake loose otherwise stable land

Question 17

Wildfires
(cause of land failure)

Answer 17

Wildfires consume vegetation, leaving slopes more exposed to heavy precipitation and failure later.

Question 18

Slope steepening
(cause of land failure)

Answer 18

This may occur naturally by rivers or ocean waves eroding the slopes, and when roads are constructed through mountainous areas.

Question 19

Overdrawing groundwater from aquifers
(cause of land failure)

Answer 19

creates Subsidence