Deck 8: Subsidence and Soils

Question 1

Which of the following does NOT cause ground subsidence?

A) Dissolving of rocks below the Earth's surface
B) Earthquakes
C) Thawing of permafrost
D) Compaction of loose sediment
E) Creation of permanently frozen ground where no thawing ever occurs

Answer 1

E

Question 2

What is karst topography?

A) A type of landscape characterized by marshes and wetlands.
B) A type of landscape that is mostly frozen and snow covered
C) A type of landscape characterized by glacial deposits
D) A ragged surface characterized by sinkholes and underground caves
E) A flat land surface used mostly for farming

Answer 2

D

Question 3

What causes volume change in expansive soil?

A) Changes in the water content
B) Changes in atmospheric pressure
C) Changes in temperature of the soil
D) Adding weight, such as a new building, on top of the soil
E) Changes in elevation of the soil

Answer 3

A

Question 4

If you were in a very cold climate and looking out at an area with many sinkholes and rough terrain, what would you most likely be looking at?

A) Expansive soils
B) Soil compaction
C) Subsidence due to groundwater pumping
D) Thermokarst
E) Disappearing springs

Question 5

Which of the following is the correct link between the soil and its horizon classification?

A) O is organic material.
B) C is zone of leaching.
C) B is organic and mineral matter.
D) K is the zone of accumulation.
E) E is the parent material.

Question 6

Which of the following is the best match between climate and soil hazard?

A) Solution sinkholes and arid climates
B) Collapsible soils and humid climates
C) Solution sinkholes and polar climates
D) Expansive soils with distinct wet and dry seasons
E) Collapsible soils and polar climates

Question 7

How good of an indicator is soil color in categorizing the soil horizon?

A) Excellent. Color always indicates an exact soil horizon.
B) It is an excellent indicator of soil horizon for well-drained soils but a poor indicator for poorly-drained soils.
C) Terrible. Different soil horizons don't have distinct color differences.
D) Reasonably good. Sometimes color can be misleading, but usually it can give you a good idea.

Question 8

In terms of soil development, what factor is most important in determining whether a soil is weakly, moderately, or well-developed?

A) Climate
B) Parent material
C) Mineral type
D) Moisture amounts
E) Age

Question 9

What is the most important soil particle that characterizes expansive soils?

A) Clay minerals
B) Calcite
C) Rock salt
D) Marble
E) Limestone

Question 10

What is the main difference between collapse sinkholes and solutional sinkholes?

A) Collapse sinkholes create a subsidence in the ground whereas solutional sinkholes have no effect on the land surface.
B) Solutional sinkholes form faster than collapse sinkholes.
C) Collapse sinkholes involve the surface rock and soil falling into an underground cave whereas solutional sinkholes form by downward dissolution from the bedrock surface.
D) Solutional sinkholes are found more often in arid regions than collapse sinkholes.
E) Solutional sinkholes are more beneficial to a location than collapse sinkholes.

Question 11

In a region susceptible to sinkhole formation, the most likely times for collapse will be

A) When groundwater levels are low.
B) When groundwater levels are high.
C) During periods of heavy rain.
D) Just before full moons.
E) During late afternoon when air temperatures are highest.

Question 12

Which of the following is NOT a normal definition of soil erosion?

A) Grain-by-grain removal of mineral and organic material in a soil by wind and water
B) Removal of soil material at an unacceptable rate
C) Dissolution of flowing acidic groundwater to produce a large underground opening
D) Removal of soil material at a rate faster than it is being produced

Question 13

What are two causes of the subsidence of New Orleans?

A) Draining of organic-rich soil and earthquakes
B) Draining of organic-rich soil and loss of supply of fine sediments by rivers
C) Draining of organic-rich soil and the dissolution of clays by flowing acidic groundwater
D) Dissolution of clays by flowing acidic groundwater and earthquakes

Question 14

What is subsidence?

A) A drop in groundwater level prior to an earthquake
B) An increase air pressure at high elevations
C) A sinking of the ground surface
D) A swelling of the ground surface
E) The rapid turbulent movement of soil and rock down a steep slope

Question 15

Which of the following is NOT a readily dissolvable rock?

A) Limestone
B) Granite
C) Gypsum
D) Marble
E) Dolostone

Question 16

Which of the following is the correct order of soil grain size from smallest to largest?

A) Clay, silt, sand, gravel
B) Silt, clay, sand, gravel
C) Sand, silt, clay, gravel
D) Gravel, sand, silt, clay
E) Silt, sand, clay, gravel

Question 17

If you were digging down into a soil, which horizon would you hit last?

A) C
B) R
C) O
D) B
E) E

Question 18

Where does the majority of soil originate from?

A) It comes from magma from the mantle.
B) It comes from volcanoes.
C) It comes from weathered rock.
D) It is brought up from the ocean floor.
E) It is produced by humans.

Question 19

What is the definition of soil according to a soil scientist?

A) Any solid earth material that has been altered by physical, chemical, and organic processes so that it can support rooted plants
B) Any dark material on earth's surface
C) Decayed plant material
D) Hard clay layer cemented with calcite, iron oxide, or silica
E) Any solid earth material that can be removed without blasting

Question 20

Which of the following does NOT usually affect the development of most soil?

A) Climate
B) Time
C) Organic processes
D) Landslides
E) Topography

Question 21

The distinct layers of a soil are called soil horizons.

Question 22

What is groundwater mining?

A) Groundwater is pumped from the ground faster than it is replenished.
B) Groundwater is used to excavate minerals.
C) Groundwater is pumped into mines to clean them.
D) Groundwater is put through a sieve to remove minerals.
E) Groundwater is used to dissolve minerals and then evaporated.

Question 23

Areas with extensive Limestone formations near the surface are particularly vulnerable to sinkholes and caves.

Question 24

The water content of a soil can be important in determining engineering properties such as the strength of a soil and its potential to shrink and swell.

Question 25

How are sinkholes related to water pollution?

A) Sinkholes are usually in swampy areas with polluted water.
B) Sinkholes are formed when polluted water reacts with the ground.
C) Sinkholes form in landfills because of too much garbage.
D) Sinkholes provide a quick route for polluted surface water to contaminate groundwater.
E) Sinkholes are filled with decaying rocks that release pollutants into the water.

Question 26

How does land subsidence contribute to water pollution?

A) Using sinkholes as landfills can cause pollutants to seep into groundwater.
B) When rocks are dissolved, dangerous chemicals enter our drinking water.
C) When the land sinks, it pulls water deep into the soil where there are pollutants.
D) Tourists who visit caves add a dangerous amount of pollutants to the water.
E) Caves host diverse species that can be a danger to groundwater.

Question 27

Weathering is the physical and chemical breakdown of rocks into smaller pieces and is involved in soil development.

Question 28

Which of the following is NOT usually caused by land subsidence or soil volume change?

A) Water pollution
B) Building collapse
C) Disease
D) Coastal flooding
E) Loss of wetlands

Question 29

Which of the following states has the greatest percentage of karst topography?

A) Kentucky
B) Nevada
C) Nebraska
D) Louisiana
E) Alaska

Question 30

Which of the following is NOT a Natural Service Function of subsidence?

A) Karst contains the world's most abundant groundwater supply.
B) Sinkholes can be used for landfills.
C) Karst plains are beautiful landscapes.
D) Caves attract tourists.
E) Caves provide unique ecosystems.

Question 31

Which of the following statements about sinkholes is FALSE?

A) Sinkholes can occur where there is soluble rock near the surface.
B) Sinkholes are usually found in remote and swampy areas.
C) Sinkholes are a widespread and costly hazard in the U.S.
D) Sinkholes can cause damage to roads and bridges.
E) Sinkholes can reveal themselves during times of drought.

Question 32

The main societal impact of soil erosion is that the eroded soil ends up filling our water reservoirs and diminishes our drinking water supply.

Question 33

Haiti faces a major problem of soil erosion because it has been growing corn without applying any fertilizer for centuries and that has depleted the soil of its nutrients.

Question 34

Which of the following is NOT an indication that there are expansive soils in an area?

A) Wavy bumps on surfaces
B) Tilting sidewalks
C) Cracks in building foundations
D) Popcorn-like weathering texture in the soil
E) Large circular holes with broken pieces of rock at the bottom

Question 35

The soil classification scheme created by soil scientists is based solely on the abundance of sand vs. clay.

Question 36

Which of the following is NOT a way that climate change can contribute to the subsidence problem?

A) Permafrost will melt causing subsidence.
B) Some soils will dry out causing them to settle.
C) Sea levels will rise sinking coastal cities that are already sinking.
D) Groundwater levels may rise or fall increasing sinkhole incidence.
E) Groundwater will warm, causing a large increase in dissolved limestone and sinkhole formation.

Question 37

Karst topography is a common type of landscape seen in many areas of the United States.

Question 38

How does pumping oil contribute to land subsidence?

A) Oil reacts with the soil causing it to fuse and take up less space.
B) Oil pumps increase the weight on the ground causing the ground to sink.
C) Oil is removed, which removes the buoyant support it provided for the earth material, causing it to be more compacted.
D) Oil reacts with the soil causing it to swell and take up more space.
E) Removing hot oil cools the earth and causes it to contract.

Question 39

Subsidence and soil volume changes are rare and don't cause very much damage in the U.S. due to advanced engineering methods.

Question 40

Which of the following statements describes subsidence at the central (San Joaquin) valley of California?

A) Gradual subsidence occurred over several decades due to the deep subsurface withdrawal of oil and gas.
B) Gradual subsidence occurred over several decades due to the withdrawal of groundwater mainly for irrigation purposes.
C) Rapid subsidence occurred due to a collapsible soil.
D) Rapid subsidence occurred due to a collapse sinkhole.

Question 41

In the U.S. subsidence and expansion and contraction of the soil are natural hazards that are well publicized and get considerable media coverage.

Question 42

Salt mines can be places for land subsidence because salt can be dissolved in water, leaving behind cavities for water to pool.

Question 43

Karst landscapes are very dangerous to humans and all measures should be taken to prevent them.

Question 44

Expansive soils are relatively rare and cause little if any damage to structures.

Question 45

Before building structures in karst regions, it can be useful to use ground penetrating radar to examine the subsurface geology.

Question 46

Sinkholes and caves involve extensive dissolution of rocks due to changing levels of groundwater.

Question 47

Organic soils cause large amounts of damage in the U.S. because they swell when wet and shrink when dry.

Question 48

Caves form in places where giant bubbles were present in the lava that formed the Earth's crust.

Question 49

Humans have contributed to the thawing of permafrost through poor building practices.

Question 50

Earthquakes cause subsidence because tectonic plates involved in subduction can actually snap downward after stress is released in an earthquake.

Question 51

The mineral composition of soils has a great influence on the type of subsidence or volume changes that will occur.

Question 52

The Mississippi Delta has experienced major subsidence over the past fifty years and that has resulted in a huge increase in the amount of wetlands.

Question 53

Sinkholes usually form when the ground becomes wet and things sink into them after a big rainstorm.

Question 54

Permafrost is particularly problematic when there is extensive thawing.

Question 55

There is little that can be done to prevent damage from expansive soils.

Question 56

In areas undergoing subsidence due to the overpumping of groundwater, flooding can be a major problem.

Question 57

Why do soil scientists and engineers have different taxonomies for classifying soil?

Question 58

Damage from soil volume change in the U.S. commonly costs more annually than all other natural disasters combined.

Question 59

Sinkhole formation is influenced by dramatic changes in the water table level that happen during wet and dry seasons.

Question 60

There have not been too many problems due to land subsidence in the United States.

Question 61

Explain the possible cause of subsidence in areas of New Orleans. Explain how you arrived at your answer.

Question 62

In the aftermath of Hurricane Katrina, the city of New Orleans received a lot of damage. One of the reasons why New Orleans was hit so hard was because of land subsidence. Explain two reasons for why the land subsided in New Orleans. Describe human activities that caused the subsidence and suggest ways that subsidence could be slowed or stopped.

Question 63

Describe what is meant by weakly developed versus well-developed soil. Give two examples to explain your answer.

Question 64

What does "restricting deltaic sedimentation" mean? Explain how it relates to subsidence.

Question 65

Coastal cities, like Venice, Italy and New Orleans are sinking. What effect will this have on these cities?

Question 66

Explain the possible cause of subsidence in areas of Florida. Explain how you arrived at your answer.

Question 67

Describe how soil develops from rocks. In this description, choose three things that affect the development of soil and explain how they affect soil development.

Question 68

Explain the possible cause of subsidence in areas of Texas. Explain how you arrived at your answer.

Question 69

Describe how volcanoes are associated with land subsidence.

Question 70

Explain the basics of how sinkholes are formed in an area.