Chapter 15 - Mass Wasting: The Work Of Gravity

Front 1

Mass wasting is __________.

Back 1

The downslope movement of material under the influence of gravity.

Front 2

A movement of fairly coherent material along a well-defined surface is called a ______.

Back 2

slide

Front 3

What is the most rapid type of mass wasting?

Back 3

Rock avalanche

Front 4

Heavy rainfalls or melting glaciers that erode volcanic deposits produce which type of mass wasting?

Back 4

Lahars

Front 5

What causes this type of mass wasting?

Back 5

Alternating freezing and thawing.

Front 6

What type of mass wasting occurs in association with permafrost.

Back 6

Solifluction

Front 7

What is the name applied to a relatively rapid downslope movement of water-rich soil and regolith in semiarid regions?

Back 7

Debris flow

Front 8

What is the estimated amount of total dollar losses from landslides in the US?

Back 8

Nearly $4 billion

Front 9

Where in North America is one of the largest known landslides that apparently raced downslope on a cushion of compressed air?

Back 9

Blackhawk landslide, San Bernardino Mountains,, California

Front 10

How does water change the strength and cohesion of clay-rich regolith or soil?

Back 10

Water lowers the strength and cohesion of both clay and soil.

Front 11

What is the angle of repose?

Back 11

A stable slope, the steepest angle of which is determined by the material in the pile.

Front 12

What type of Mass Wasting would most likely be triggered by an earthquake?

Back 12

Rock avalanche

Front 13

How does the gravitational force pulling a particle downward along the land surface vary with the inclination of the slope?

Back 13

It will decrease as the slope angle is lessened.

Front 14

Why was the Alaskan pipeline built above ground and insulated?

Back 14

To protect the pipeline against damage because of thawing ground.

Front 15

As an erosional process, how is mass wasting unique from wind, water, and ice?

Back 15

Mass wasting does not require a transporting medium.

Front 16

During wet weather or times when snow is melting, sometimes the downhill toe of a slump becomes an _____.

Back 16

earthflow

Front 17

What was a major factor leading to the Gros Ventre, WY, slide?

Back 17

Soils and shallow bedrock were very wet and locally saturated. Heavy rains and melting snow triggered the major rockslide, which made the sandston slide down the slope on top of wet clay.

Front 18

What type of mass wasting operates primarily in areas of permafrost?

Back 18

Solifluction

Front 19

Is Geologic age a factor affecting mass wasting?

Back 19

No

Front 20

What is the controlling force in mass wasting?

Back 20

gravity

Front 21

What caused the 1985 mudflows on the Nevado del Ruiz volcano?

Back 21

Hot ash fell onto snow near the summit, this melted the snow and produced torrents of hot, viscous mud, ash, and debris.

Front 22

Which type of mass wasting process involves movement of rock on a zone of compressed air?

Back 22

Rock avalanche

Front 23

What are lahars?

Back 23

mudflows

Front 24

What type of mass wasting is common wherever water cannot escape from the saturated surface layer by infiltrating to deeper levels?

Back 24

Solifluction - when soil is saturated with water, the soggy mass may flow downslope at a rate of a few millimeters or a few centimeters per day or per year.

Front 25

Where do rock avalanches occur?

Back 25

Where there is exposed rock that is able to fall downslope.

Front 26

Where does soil creep operate?

Back 26

Places that have alternating expansion and contraction of surface material caused by freezing and thawing or wetting and drying.

Front 27

What types of climates do mudflows operate?

Back 27

Many, but most frequently in semiarid mountainous regions.

Front 28

Does mass wasting depend on wind, water, and ice?

Back 28

No

Front 29

What is slumping?

Back 29

A block or blocks of unconsolidated regolith slide downhill along a curved slip surface

Front 30

Which mass wasting process has the slowest rate of movement?

Back 30

Creep

Front 31

What term denotes the exposed, crescent-shaped rupture surface at the head of a slump?

Back 31

Scarp

Front 32

What type of mass wasting is best described as a a process in which a block or blocks of unconsolidated regolith slide downhill along a curved slip surface?

Back 32

Slumping

Front 33

What type of mass wasting is a process in which blocks of hard bedrock break loose rapidly slide downhill along fracture surfaces?

Back 33

rockslide

Front 34

What type of mass wasting is a process in which the soil and regolith move downhill very slowly?

Back 34

creep

Front 35

What type of mass wasting is a process in which a mass of soil or regolith becomes saturated with water and suddenly flows downhill to the base of the slope?

Back 35

mudslide

Front 36

What mass movement is most likely to occur in a geologic setting where the rock strata are inclined?

Back 36

Rockslide

Front 37

How do freezing, thawing, wetting, and drying contribute to soil creep?

Back 37

The soil expands and contracts, lifting particles and dropping them a slight distance downslope.

Front 38

What can happen to the downhill toe of a slump during wet weather or times when snow is melting?

Back 38

The toe can become an earthflow.

Front 39

What is the primary way in which talus slopes are built?

Back 39

Rockfalls

Front 40

What are possible indicators that creep is taking place?

Back 40

Tilted fences or power line poles

Curved tree trunks

Cracks in roads or sidewalks

Front 41

Is soil thickness and indicator of creep?

Back 41

no

Front 42

Earthflows most often form on hillsides in ______ areas during times of _______ or ________.

Back 42

Humid

Heavy precipitation

snowmelt

Front 43

Debris flow is also known as a _______.

Back 43

mudslide

Front 44

What happened in Vaiont Canyon, Italy, 1963?

Back 44

A huge mass of soil and rock suddenly slid into a water-filled reservoir. (the presence of a dam)