Deck 9: Sinkholes Land Subsidence and Swelling Soils

Question 1

In addition to limestone, evaporites like ____ and ____ can create underground cavities.

A)smectite; salt
B)smectite; gypsum
C)permafrost; smectite
D)gypsum; karst
E)salt; gypsum

Answer 1

A

Question 2

What creates caverns in limestone rock?

A)Underground streams erode the walls of the channels they flow through.
B)Limestone is deposited as a sediment, and caverns exist where organic material was trapped and decomposed.
C)Earthquakes create gaps at weak boundaries in the limestone.
D)Limestone dissolves in the presence of salt, and creates caverns when located under the sea.
E)Acidic rainwater dissolves limestone rock, leaving empty caverns.

Answer 2

E

Question 3

Rainwater becomes acidic as it dissolves limestone.

Answer 3

False

Question 4

Sinkholes appear suddenly, and cannot be detected by precursor events.

Question 5

In order for limestone to collapse to form a major sinkhole, the ground above must be ____.

A)thin and porous so that rainwater passes through easily
B)small-grained so the soils can percolate through fissures
C)thick and rich in cohesive clay to allow a cavern to form
D)high in peat, allowing decomposition in the presence of oxygen
E)acidic, to speed the dissolution process

Question 6

Sinkholes are triggered when the groundwater level rises.

Question 7

The effects of land subsidence due to groundwater extraction are generally ____.

A)problems for a period of months, until more groundwater seeps in to deep clays
B)permanent and irreversible
C)in effect for several years, until major storms irrigate the area
D)reversible by returning water to the aquifer
E)unpredictable and impossible to plan for effectively

Question 8

Limestone consists of rock made from ____.

A)carbon dioxide
B)carbonic acid
C)sodium bicarbonate
D)calcium carbonate
E)carbon silicate

Question 9

The uneven, potholed surface of karst is caused by ____.

A)erosion from ancient streambeds
B)the pattern of deposited material from glaciers
C)hardening of volcanic ash into tuff
D)swelling due to the absorption of water
E)the dissolution of the surface in the presence of acids

Question 10

Soils with a high smectite clay composition are at risk of land subsidence.

Question 11

Land subsidence increases the hazard of ____.

A)earthquakes
B)hurricanes
C)landslides
D)drought
E)flooding

Question 12

Swelling soils can lead to saltwater intrusion into groundwater.

Question 13

Ground settling from thaws is only found in the area around the Arctic Ocean.

Question 14

Land subsidence that results from petroleum mining ____.

A)is a necessary cost of fossil fuel production
B)can be mitigated by pumping fluid into the well
C)is a problem in the Middle East, but not in the United States ​
D)will be avoided if the well hole is sealed and capped after use
E)follows a different process than subsidence from groundwater mining

Question 15

Global climate change has increased the depth of permafrost thaw.

Question 16

Sinkholes are formed as a result of the collapse of a limestone cavern.

Question 17

A sinkhole is most likely to form ____.

A)after a hurricane ​
B)during a thunderstorm
C)any time during the rainy season
D)after an earthquake
E)at the end of a dry season

Question 18

Peat exposed to oxygen will become acidic and increase limestone dissolution.

Question 19

In which state would you NOT expect to find karst?

A)Florida
B)California
C)Kentucky
D)Missouri
E)Pennsylvania

Question 20

Vegetation increases the swelling of soils.

Question 21

Water and soil percolating through karst fissures can create a small depression through the process of _______________.

Question 22

Discuss three factors that increase ground settling due to thaw in Arctic regions.

Question 23

Clays play a role in land subsidence by ____.

A)weighing down organic material and compacting it, causing subsidence
B)swelling and causing runoff and subsidence in adjacent areas
C)absorbing moisture to counteract subsidence
D)blocking the absorption of groundwater by the aquifer, making subsidence likely downstream
E)collapsing into compact layers when dried, increasing subsidence

Question 24

_______________ is soil containing frozen groundwater.

Question 25

Why is groundwater mining linked to ground subsidence? Discuss the factors that create the subsidence and why the damage cannot be repaired.

Question 26

The decomposition of peat layers in soils ____.

A)releases sodium bicarbonate into groundwater
B)can result in flooding in land drained for farming
C)is usually caused when the peat layer is exposed by digging or tilling
D)happens during abnormally dry seasons
E)transforms the peat into clay

Question 27

The level to which _______________ rises in a well is the location of the water table.

Question 28

Landslides due to the melting of permafrost ____.

A)are shallow and only affect a few meters as the thawed layer slides off the remaining permafrost
B)create rotational slumps as deeper thawed areas loosen the connection of permafrost to the supporting layers
C)are extensive and damaging, where lakes and streams warm the ground
D)create large translational slumps as unthawed permafrost slides over subsurface meltwater
E)can be avoided if vegetation maintains a deep snow cover

Question 29

You are a hotel manager and your employer has given you a choice of locations in Florida to relocate to as part of a promotion. You have been offered positions in Tampa (central Gulf Coast), Orlando (inland central Florida), Tallahassee (northern Florida Panhandle), and Miami (south Atlantic Coast). Considering only the hazard represented by sinkholes, which location will be safest and why?

Question 30

The damage due to swelling soils results in losses of ____ in the United States.

A)tens of millions of dollars, primarily through associated maintenance of cars and trucks,
B)tens of millions of dollars, primarily through damage to residences and businesses,
C)tens of millions of dollars, primarily in disruption of truck and train transport,
D)billions of dollars, primarily through damage to highways and streets,
E)billions of dollars, primarily through damage to residential homes,

Question 31

A(n) _______________ hangs from the ceiling of a cavern.

Question 32

Swelling soils are typically due to ____.

A)kaolinite clay expelling, water which increases the volume of sand layers
B)heat, which increases the volume of water bound in clay layers
C)freezing water, which expands, increasing the volume of clay layers
D)smectite clay increasing in volume as it absorbs water
E)landslides removing pressure from clay layers, allowing them to increase in volume

Question 33

Exposure of limestone rock creates an uneven and potholed surface called _______________.

Question 34

Thawing permafrost _______________.

A)creates problems for oil pipelines, which run underground in high latitudes
B)reduces climate change dangers by absorbing atmospheric heat
C)increases climate change dangers by injecting warm water into the Arctic Ocean
D)puts buildings at risk of damage, but does not disrupt transportation
E)leads to a reduction in biodiversity by removing vegetation that protects snowbanks

Question 35

_______________ clay is most involved with swelling soils.

Question 36

In order to dissolve limestone, groundwater must be slightly _______________.