Ch 10 Mass Wasiting

Which statement best describes slumping, a mass wasting process?

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

Consider a steep highway cut made by removing slightly weathered to fresh, fractured, granite bedrock. Which of the following situations is most stable against rockslides?

A) one set of widely spaced, sub-horizontal fractures

Why was the Alaskan pipeline built above ground and insulated?

A) to protect the pipeline against damage due to thawing ground and tot keep the crude oil hot and fluid

Which one of the following operates primarily in areas of permafrost?

B) Soliflucation

All of the following are possible indicators that creep is occurring except for ____

B) an extremely thick soil profile

Consider a weathered rock or soil particle lying on a slope. How will the gravitational force pulling the particle downward along the land surface vary with the inclination of the slope?

B) it will decrease as the slope angle is lessened

A geologist wants to locate a horizontal coal bed on a soil-covered slope where soil creep is active. A distinctive sandstone bed underlies the coal bed. On the basis of weathered sandstone fragments in the soil, where is the coal bed?

B) just above the highest piece of sandstone seen in the soil

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

B) mass wasting does not require a transporting medium

____ involves movement on a zone of compressed air.

C) a rock avalanche

Which of the following statements concerning mudflows is not true?

C) mudflows deposit talus slopes

The most rapid type of mass movement is a ____

C) rock avalanche

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

C) the soil expands and contracts, lifting particles and dropping them a slight distance downslope

_____ denotes the exposed, crescent-shaped rupture surface at the head of a slump.

D) Scarp

Which mass wasting process has the slowest rate of movement?

D) creep

All of the following are factors affecting mass wasting except for ____ .

D) geologic age

Of the following, which one would most likely be triggered by an earthuake?

D) rock avalanche

Which of the following mass movements is most likely to occur in a geologic setting where the rock strata are inclined?

D) rockslide

How do the strength and cohesion of clay-rich regolith or soil change with the addition nof water?

D) water lowers the strength and cohesion

Slump describes the very slow, downhill movement of soil and regolith.

False

The steepest, stable, slope angle possible is unconsolidated , granular materials like sand and gravel is called the angle of retention.

False

Bedding planes and fractures can both act as a slip surfaces for rockslides.

True

Solifluction occurs during the warmer summer months

True

repeated freezing and thawing can be important in soil creep movements.

True

a triggering mechanism, such as heavy rains or an earthquake are necessary for mass wasting to occur.

false

Lahars are essentially mudflows associated with volcanoes and volcanism.

true

a scarp is the exposed portion of the rupture surface beneath a slump block.

true

earthflows and slumps generally involve movement of unconsolidated or weakly consolidated soil and regolith.

true

solifluction is an important mass wasting process in areas of permafrost

true