,SOLUTION MANUAL FOR Natural Hazards and
Disasters 6th Edition by Donald Hyndman
Notes
1- The file is chapter after chapter.
2- We have shown you few pages sample.
3- The file contains all Appendix and Excel sheet
if it exists.
4- We have all what you need, we make update
at every time. There are many new editions
waiting you.
5- If you think you purchased the wrong file You
can contact us at every time, we can replace it
with true one.
Our email:
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 1: Natural Hazards and Disasters
Solution and Answer Guide
HYNDMAN, NATURAL HAZARDS AND DISASTERS 6E, © 2025, 9780357851579;
CHAPTER 1: NATURAL HAZARDS AND DISASTERS
TABLE OF CONTENTS
Answers to Questions for Review ............................................................................................. 1
Answers to Critical Thinking Questions ................................................................................... 3
ANSWERS TO QUESTIONS FOR REVIEW
1. What are some of the reasons people live in areas prone to natural disasters?
Answer:
For the scenic view, to experience picturesque streams, to enjoy the seclusion and scenery
of the woods, to enjoy ocean views or the beach more intimately, for fertile land, and for
cheap land.
2. Is the geological landscape controlled by gradual and unrelenting processes or intermittent large
events with little action in between? Provide an example to illustrate.
Answer:
Intermittent large events: streams run clear most of the year but get muddy and erode their
channels during floods.
3. Some natural disasters happen when the equilibrium of a system is disrupted. What are some
examples?
Answer:
Slopes are oversteepened by roadcuts that causes slope failure or stress applied to Earth’s
surface produces strain on a body of rock, ultimately resulting in an earthquake. A bulge may
form on a volcano as molten magma slowly rises into it; then it collapses as the volcano suddenly
erupts.
4. Contrast the general nature of catastrophic losses in developed countries versus low-income
countries. Explain why this is the case.
Answer:
In developing countries, there are greater numbers of deaths from natural disasters, whereas in
developed countries, there are typically greater economic losses. Wealth and education of a
country are determining factors to the type of losses or damage.
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 1
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 1: Natural Hazards and Disasters
5. What are the three most deadly hazards in the United States?
Answer:
Heat and drought, flooding, and tornado are the three most deadly hazards.
6. What are the main reasons for the ever-increasing costs of catastrophic natural events?
Answer:
Overall increase in world population and human migration to more hazardous areas. It is also a
function of increased value of properties at risk.
7. Why are most natural events not perfectly cyclic, even though some processes that influence
them are cyclic?
Answer:
Multiple independent variables affect most events and overlapping “cycles” give noncyclic
variation. Even with cyclic events, overlapping cycles make resultant extremes noncyclic, which
affects the predictability of a specific event. So far as anyone can tell, most episodes, large and
small, occur at seemingly random and essentially unpredictable intervals.
8. What is the difference between a prediction and a forecast?
Answer:
A prediction provides an exact time, location, and magnitude of a hazardous event, while a
forecast provides the probability of a natural disaster occurring in a region within a few decades.
9. Give an example of a feedback effect in natural processes.
Answer:
Global warming causes more rapid melting of Arctic sea ice, which lessens the amount of white
ice and increases the amount of dark seawater in the world. Darker seawater absorbs more solar
energy than white ice, causing even more sea ice melting.
10. Give an example of a fractal system.
Answer:
Numerous small streams (e.g., viewed at a close scale such as part of a state), many larger
streams (e.g., viewed over a larger area such as the United States), and very few giant rivers
(e.g., the Mississippi as viewed on a world map). Also, numerous small landslides, fewer large
landslides, and only rarely a giant landslide.
11. Describe the general relationship between the frequency and magnitude of an event.
Answer:
The magnitude of an event is inversely proportional to the frequency of the type of event: as
frequency decreases, magnitude increases. By the Numbers 1-1.
12. If the recurrence interval for a stream flood has been established at 100 years and the stream
flooded last year, what is the probability of the stream flooding again this year?
Answer:
One in hundred (or 1/100)
13. What are the two main factors insurance companies use to determine the cost of an insurance
policy for a natural hazard?
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 2
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 1: Natural Hazards and Disasters
Answer:
The probability of an event occurrence (e.g., recurrence interval) and the cost of the probable loss
(in dollars) from the event. By the Numbers 1-2.
14. When people or governmental agencies try to restrict or control the activities of nature, what is
the general result?
Answer:
The problem is transferred to somewhere else or onto someone else. For example, constricting
river flow with a levee backs up floodwater, potentially causing flooding of an upstream neighbor’s
property.
ANSWERS TO CRITICAL THINKING QUESTIONS
1. If people should not live in especially dangerous areas, what beneficial uses could there be for
those areas? What are some examples?
Answer:
Volcanic areas: The volcanic ash in these regions weathers into richly productive soil, making
them good farmland.
Floodplains: Large floodplains offer good agricultural soil, inexpensive land, and natural
transportation corridors, attracting people for farming and settlement.
Coastal areas: Despite the risks of coastal storms, living along the coast provides ocean views
and an intimate experience with the sea.
2. What responsibility does the government have to ensure that its citizens are safe from natural
hazards? Conversely, what freedom should individuals have to choose where they want to live?
Answer:
The government shoulders the responsibility of safeguarding citizens from natural hazards
through research, forecasting, and mitigation efforts, including funding programs and relocating
vulnerable individuals. Yet, individuals should retain the freedom to choose their residence, albeit
within the confines of government measures aimed at reducing risks and losses from natural
disasters.
3. A small town suffering economic losses from the closure of a factory considers a plan to build a
new housing development in an area where there is a record of infrequent flooding. Make a case
for and against this development. In your case for the development, describe what measures
need to be taken to minimize hazards.
Answer:
Case for Development: Building a new housing development could rejuvenate the town’s
economy, providing jobs and attracting new residents. To minimize flood hazards, thorough risk
assessments, improved drainage systems, raised building foundations, and community education
on evacuation plans are essential, ensuring safety and sustainable growth.
4. Should people be permitted to build in hazardous sites? Should they expect government help in
case of a disaster? Should they be required to pay for all costs incurred in a disaster?
Answer:
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 3
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 1: Natural Hazards and Disasters
Building in hazardous sites should be regulated to minimize risk. While government aid may be
provided in disasters, individuals should primarily bear responsibility for their choices, including
covering costs incurred due to their decision to build in such areas.
5. What are the main natural hazards in the region where you currently live or where you grew up?
Answer:
The United States faces various natural hazards across its regions. Common ones include
hurricanes along the Gulf Coast and East Coast, tornadoes in the Midwest and South,
earthquakes in the West, wildfires throughout the West and Southwest, and flooding in many
parts of the country.
6. If you sell a house that is later damaged by a landslide, who is responsible? That is, what are the
main considerations?
Answer:
Developers, motivated by profit, may prioritize financial gain over the potential risks to buyers. If the
seller knew about the landslide risk and failed to disclose it, they could be liable. The terms of the sale
contract, including any warranties or indemnifications, may allocate liability. Some jurisdictions have
regulations governing liability for property sales and natural disasters. Ultimately, determining
responsibility often involves legal analysis and can vary based on specific circumstances and
applicable laws.
7. When the federal government provides funds to protect people’s homes from floods or wildfires,
individual homeowners benefit at the expense of taxpayers. What are the two main types of
alternatives to eliminate taxpayer expense for natural hazard losses?
Answer:
Public awareness and education programs.
8. What is meant by the expression “Those who ignore the past are condemned to repeat it”?
Provide an example related to natural hazards.
Answer:
The expression means that failure to learn from historical events leads to their recurrence. For
instance, neglecting past instances of flooding and building in flood-prone areas without adequate
precautions can result in repeated property damage and loss of life.
9. When we note that people need to take responsibility for their own actions when living in a
hazardous environment, what is different about the behavior of low-income people living in
underdeveloped countries?
Answer:
Low-income people in underdeveloped countries may have fewer resources and options to
mitigate risks in hazardous environments. They may lack access to safe housing, infrastructure,
and insurance, making it challenging to take responsibility for their actions in the same way as
those in more developed regions.
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 4
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 2: Plate Tectonics and Physical Hazards
Solution and Answer Guide
HYNDMAN, NATURAL HAZARDS AND DISASTERS 6E, © 2025, 9780357851579;
CHAPTER 2: PLATE TECTONICS AND PHYSICAL HAZARDS
TABLE OF CONTENTS
Answers to Questions for Review ............................................................................................. 1
Answers to Critical Thinking Questions ................................................................................... 3
ANSWERS TO QUESTIONS FOR REVIEW
1. What are the differences between Earth’s crust, lithosphere, asthenosphere, and mantle?
Answer:
Earth’s crust overlies mantle—distinguished by composition: Oceanic crust is basaltic
composition, and continental crust is “granitic” composition. The ocean’s lithosphere is composed
of a low-silica crust, whereas the continental crust is largely composed of high-silica-content
minerals. Earth’s lithosphere overlies asthenosphere—distinguished by rock
properties/behavior/strength: Lithosphere is rigid; asthenosphere is plastic/easily deformed.
2. What do oceanic and continental lithosphere consist of and how thick are they?
Answer:
Oceanic lithosphere is generally only about 60 km thick; its top 7 km are a low-silica basalt-
composition crust.
3. What are the main types of lithospheric plate boundaries, described in terms of relative motions?
Provide a real example of each (by name or location).
Answer:
Divergent Boundary: Plates move apart, new crust is created. Examples are the Mid-Atlantic
Ocean Ridge and the East African Rift Zone.
Convergent Boundary: Plates collide, old crust is destroyed. Examples include ocean-continent
collision, such as the Cascade Ranges and the Andes in South America; ocean-ocean collision,
such as the Japanese islands and Indonesia; and continent-continent collision, such as the
Himalayas.
Transform Boundary: Crust is neither created nor destroyed, horizontal displacement. An
example is the San Andreas Fault.
4. Why does oceanic lithosphere almost always sink beneath continental lithosphere at convergent
zones?
Answer:
Oceanic lithosphere is denser/heavier than continental lithosphere because it contains more iron-
and magnesium-rich minerals.
5. Along which type(s) of lithospheric plate boundary are large earthquakes common? Why?
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 1
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 2: Plate Tectonics and Physical Hazards
Answer:
Although earthquakes occur at all plate boundaries, convergent boundaries produce the largest
earthquakes. As one plate is being subducted beneath another, the overlying crust deforms.
Eventually the stress applied to the rock is greater than the strength of the rock, causing the crust
to fracture.
6. Along which type(s) of lithospheric plate boundary are large volcanoes most common? Provide
an example.
Answer:
Continent–ocean convergent boundary (Cascadia subduction zone/High Cascades volcanoes)
and ocean-ocean convergent boundary (Japanese islands).
7. What direction is the Pacific Plate currently moving, based on FIGURE 2-15? How fast is this
plate moving?
Answer:
West-northwest; approximately 9 cm per year.
8. Before people understood plate tectonics, what evidence led some scientists to believe in
continental drift?
Answer:
Geographic fit of continents by matching coastlines across the Atlantic Ocean, match of rock
formations across the Atlantic Ocean, match of ages of continental rocks across the Atlantic
Ocean, match of fossils across the Atlantic Ocean, and glacial patterns.
9. If the coastlines across the Atlantic Ocean are spreading apart, why isn’t the Atlantic Ocean
deepest in its center?
Answer:
New ocean floor wells up and forms a ridge in the middle of the Atlantic Ocean (Mid-Atlantic
Ridge).
10. What evidence confirmed seafloor spreading?
Answer:
Reversals of the Earth’s magnetic field are preserved in ocean-floor basalt, as matching patterns
across the mid-oceanic ridge. The youngest ocean-floor basalt is at the ridge.
11. Why are high volcanoes such as the Cascades found on the continents and in a row parallel to
the continental margin?
Answer:
They are the surface expression of the active subduction zone.
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 2
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 2: Plate Tectonics and Physical Hazards
12. Explain how the modern theory of plate tectonics developed in the context of the scientific
method.
Answer:
The scientific method is based on logical analysis of data to solve problems. The evidence for
continental drift and additional data such as magnetic patterns in the ocean floor were used to
test the hypothesis of plate tectonics.
13. How does the height of a mountain range compare with the thickness of the crust or lithosphere
below the mountain? Relate this to the percentage of an iceberg above the water line.
Answer:
The height of an iceberg above the water line or a mountain range above the average continent is
dependent on the difference in density between the submerged part of the iceberg or mountain
and the surrounding water or mantle. Because the density of ice is 90% of the density of the
surrounding water, 10% of the iceberg is above the water. The density of average continental
rocks is 84% of the density of the mantle. This results in 16% of the mountain being exposed.
ANSWERS TO CRITICAL THINKING QUESTIONS
1. Explain the role of Earth material densities with respect to Earth’s features such as mountains
and mid-oceanic ridges. For example, why is the top of basaltic crust below sea level while the
surface of granitic crust is generally above sea level?
Answer:
The role of Earth material densities in shaping features like mountains and mid-oceanic ridges is
significant. For instance, the top of basaltic crust is below sea level because it is denser, while the
surface of granitic crust is generally above sea level due to its lower density. This phenomenon is
explained by isostasy, where the less dense continental crust floats higher on the denser mantle,
while the thinner oceanic crust sinks lower. Major mountain ranges often have deep roots with
thicker crust compared to adjacent areas, indicating subduction of denser oceanic crust beneath
a lighter continental crust. This subduction process, driven by plate tectonics and seafloor
spreading, results in volcanic activity and earthquakes, ultimately shaping Earth's topography.
2. The Basin and Range region of Nevada and Utah is a continental spreading zone. Because it is
pulling apart, why isn’t its elevation low, rather than as high as it is? Why isn’t it an ocean?
Answer:
The Basin and Range region of Nevada and Utah, despite undergoing continental spreading,
does not have a low elevation as one might expect. This is because the spreading occurs at a
slow rate, preventing the land from sinking to form a lower elevation. Additionally, the region
cannot split the continental plate quickly enough to create a new ocean floor, so it does not
become an ocean. Therefore, its elevation remains relatively high, and it retains its continental
character.
3. The scientific community initially rejected Wegener’s hypothesis of continental drift and remained
skeptical for decades. Does skepticism help or hinder scientific progress?
Answer:
Skepticism initially hindered scientific progress regarding Wegener’s hypothesis of continental
drift. Many scientists rejected his theory because they believed the proposed mechanism was
physically impossible. However, this skepticism prompted further investigation and the
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 3
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 2: Plate Tectonics and Physical Hazards
development of alternative hypotheses. Eventually, Harry Hess proposed the idea of ocean floors
acting as giant conveyor belts, which laid the foundation for the modern theory of plate tectonics.
Thus, while skepticism initially slowed progress, it ultimately contributed to scientific advancement
by prompting critical analysis and the development of more accurate theories.
4. In formal scientific usage, hypothesis often indicates a tentative conclusion, whereas a scientific
theory is based on evidence tested over a long time and is considered to be scientific fact. What
other scientific issues have caused broad debate in social and political culture? Are they well-
supported scientific theories or just hypotheses?
Answer:
Students’ answers will vary depending on the source selected. In addition to the hypothesis-
theory distinction, debates in social and political realms often surround topics like climate change,
genetically modified organisms (GMOs), and vaccinations. While supported by substantial
evidence, they encounter resistance and controversy. Climate change is supported by
overwhelming scientific consensus. GMO safety is generally affirmed, though specific
applications raise concerns. Vaccinations are backed by extensive research, but skepticism
persists, challenging their acceptance as established scientific fact.
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 4
publicly accessible website, in whole or in part.
Disasters 6th Edition by Donald Hyndman
Notes
1- The file is chapter after chapter.
2- We have shown you few pages sample.
3- The file contains all Appendix and Excel sheet
if it exists.
4- We have all what you need, we make update
at every time. There are many new editions
waiting you.
5- If you think you purchased the wrong file You
can contact us at every time, we can replace it
with true one.
Our email:
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 1: Natural Hazards and Disasters
Solution and Answer Guide
HYNDMAN, NATURAL HAZARDS AND DISASTERS 6E, © 2025, 9780357851579;
CHAPTER 1: NATURAL HAZARDS AND DISASTERS
TABLE OF CONTENTS
Answers to Questions for Review ............................................................................................. 1
Answers to Critical Thinking Questions ................................................................................... 3
ANSWERS TO QUESTIONS FOR REVIEW
1. What are some of the reasons people live in areas prone to natural disasters?
Answer:
For the scenic view, to experience picturesque streams, to enjoy the seclusion and scenery
of the woods, to enjoy ocean views or the beach more intimately, for fertile land, and for
cheap land.
2. Is the geological landscape controlled by gradual and unrelenting processes or intermittent large
events with little action in between? Provide an example to illustrate.
Answer:
Intermittent large events: streams run clear most of the year but get muddy and erode their
channels during floods.
3. Some natural disasters happen when the equilibrium of a system is disrupted. What are some
examples?
Answer:
Slopes are oversteepened by roadcuts that causes slope failure or stress applied to Earth’s
surface produces strain on a body of rock, ultimately resulting in an earthquake. A bulge may
form on a volcano as molten magma slowly rises into it; then it collapses as the volcano suddenly
erupts.
4. Contrast the general nature of catastrophic losses in developed countries versus low-income
countries. Explain why this is the case.
Answer:
In developing countries, there are greater numbers of deaths from natural disasters, whereas in
developed countries, there are typically greater economic losses. Wealth and education of a
country are determining factors to the type of losses or damage.
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 1
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 1: Natural Hazards and Disasters
5. What are the three most deadly hazards in the United States?
Answer:
Heat and drought, flooding, and tornado are the three most deadly hazards.
6. What are the main reasons for the ever-increasing costs of catastrophic natural events?
Answer:
Overall increase in world population and human migration to more hazardous areas. It is also a
function of increased value of properties at risk.
7. Why are most natural events not perfectly cyclic, even though some processes that influence
them are cyclic?
Answer:
Multiple independent variables affect most events and overlapping “cycles” give noncyclic
variation. Even with cyclic events, overlapping cycles make resultant extremes noncyclic, which
affects the predictability of a specific event. So far as anyone can tell, most episodes, large and
small, occur at seemingly random and essentially unpredictable intervals.
8. What is the difference between a prediction and a forecast?
Answer:
A prediction provides an exact time, location, and magnitude of a hazardous event, while a
forecast provides the probability of a natural disaster occurring in a region within a few decades.
9. Give an example of a feedback effect in natural processes.
Answer:
Global warming causes more rapid melting of Arctic sea ice, which lessens the amount of white
ice and increases the amount of dark seawater in the world. Darker seawater absorbs more solar
energy than white ice, causing even more sea ice melting.
10. Give an example of a fractal system.
Answer:
Numerous small streams (e.g., viewed at a close scale such as part of a state), many larger
streams (e.g., viewed over a larger area such as the United States), and very few giant rivers
(e.g., the Mississippi as viewed on a world map). Also, numerous small landslides, fewer large
landslides, and only rarely a giant landslide.
11. Describe the general relationship between the frequency and magnitude of an event.
Answer:
The magnitude of an event is inversely proportional to the frequency of the type of event: as
frequency decreases, magnitude increases. By the Numbers 1-1.
12. If the recurrence interval for a stream flood has been established at 100 years and the stream
flooded last year, what is the probability of the stream flooding again this year?
Answer:
One in hundred (or 1/100)
13. What are the two main factors insurance companies use to determine the cost of an insurance
policy for a natural hazard?
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 2
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 1: Natural Hazards and Disasters
Answer:
The probability of an event occurrence (e.g., recurrence interval) and the cost of the probable loss
(in dollars) from the event. By the Numbers 1-2.
14. When people or governmental agencies try to restrict or control the activities of nature, what is
the general result?
Answer:
The problem is transferred to somewhere else or onto someone else. For example, constricting
river flow with a levee backs up floodwater, potentially causing flooding of an upstream neighbor’s
property.
ANSWERS TO CRITICAL THINKING QUESTIONS
1. If people should not live in especially dangerous areas, what beneficial uses could there be for
those areas? What are some examples?
Answer:
Volcanic areas: The volcanic ash in these regions weathers into richly productive soil, making
them good farmland.
Floodplains: Large floodplains offer good agricultural soil, inexpensive land, and natural
transportation corridors, attracting people for farming and settlement.
Coastal areas: Despite the risks of coastal storms, living along the coast provides ocean views
and an intimate experience with the sea.
2. What responsibility does the government have to ensure that its citizens are safe from natural
hazards? Conversely, what freedom should individuals have to choose where they want to live?
Answer:
The government shoulders the responsibility of safeguarding citizens from natural hazards
through research, forecasting, and mitigation efforts, including funding programs and relocating
vulnerable individuals. Yet, individuals should retain the freedom to choose their residence, albeit
within the confines of government measures aimed at reducing risks and losses from natural
disasters.
3. A small town suffering economic losses from the closure of a factory considers a plan to build a
new housing development in an area where there is a record of infrequent flooding. Make a case
for and against this development. In your case for the development, describe what measures
need to be taken to minimize hazards.
Answer:
Case for Development: Building a new housing development could rejuvenate the town’s
economy, providing jobs and attracting new residents. To minimize flood hazards, thorough risk
assessments, improved drainage systems, raised building foundations, and community education
on evacuation plans are essential, ensuring safety and sustainable growth.
4. Should people be permitted to build in hazardous sites? Should they expect government help in
case of a disaster? Should they be required to pay for all costs incurred in a disaster?
Answer:
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 3
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 1: Natural Hazards and Disasters
Building in hazardous sites should be regulated to minimize risk. While government aid may be
provided in disasters, individuals should primarily bear responsibility for their choices, including
covering costs incurred due to their decision to build in such areas.
5. What are the main natural hazards in the region where you currently live or where you grew up?
Answer:
The United States faces various natural hazards across its regions. Common ones include
hurricanes along the Gulf Coast and East Coast, tornadoes in the Midwest and South,
earthquakes in the West, wildfires throughout the West and Southwest, and flooding in many
parts of the country.
6. If you sell a house that is later damaged by a landslide, who is responsible? That is, what are the
main considerations?
Answer:
Developers, motivated by profit, may prioritize financial gain over the potential risks to buyers. If the
seller knew about the landslide risk and failed to disclose it, they could be liable. The terms of the sale
contract, including any warranties or indemnifications, may allocate liability. Some jurisdictions have
regulations governing liability for property sales and natural disasters. Ultimately, determining
responsibility often involves legal analysis and can vary based on specific circumstances and
applicable laws.
7. When the federal government provides funds to protect people’s homes from floods or wildfires,
individual homeowners benefit at the expense of taxpayers. What are the two main types of
alternatives to eliminate taxpayer expense for natural hazard losses?
Answer:
Public awareness and education programs.
8. What is meant by the expression “Those who ignore the past are condemned to repeat it”?
Provide an example related to natural hazards.
Answer:
The expression means that failure to learn from historical events leads to their recurrence. For
instance, neglecting past instances of flooding and building in flood-prone areas without adequate
precautions can result in repeated property damage and loss of life.
9. When we note that people need to take responsibility for their own actions when living in a
hazardous environment, what is different about the behavior of low-income people living in
underdeveloped countries?
Answer:
Low-income people in underdeveloped countries may have fewer resources and options to
mitigate risks in hazardous environments. They may lack access to safe housing, infrastructure,
and insurance, making it challenging to take responsibility for their actions in the same way as
those in more developed regions.
© 2025 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 4
publicly accessible website, in whole or in part.
, Solution and Answer Guide: Hyndman, Natural Hazards and Disasters 6e, © 2025, 9780357851579;
Chapter 2: Plate Tectonics and Physical Hazards
Solution and Answer Guide
HYNDMAN, NATURAL HAZARDS AND DISASTERS 6E, © 2025, 9780357851579;
CHAPTER 2: PLATE TECTONICS AND PHYSICAL HAZARDS
TABLE OF CONTENTS
Answers to Questions for Review ............................................................................................. 1
Answers to Critical Thinking Questions ................................................................................... 3
ANSWERS TO QUESTIONS FOR REVIEW
1. What are the differences between Earth’s crust, lithosphere, asthenosphere, and mantle?
Answer:
Earth’s crust overlies mantle—distinguished by composition: Oceanic crust is basaltic
composition, and continental crust is “granitic” composition. The ocean’s lithosphere is composed
of a low-silica crust, whereas the continental crust is largely composed of high-silica-content
minerals. Earth’s lithosphere overlies asthenosphere—distinguished by rock
properties/behavior/strength: Lithosphere is rigid; asthenosphere is plastic/easily deformed.
2. What do oceanic and continental lithosphere consist of and how thick are they?
Answer:
Oceanic lithosphere is generally only about 60 km thick; its top 7 km are a low-silica basalt-
composition crust.
3. What are the main types of lithospheric plate boundaries, described in terms of relative motions?
Provide a real example of each (by name or location).
Answer:
Divergent Boundary: Plates move apart, new crust is created. Examples are the Mid-Atlantic
Ocean Ridge and the East African Rift Zone.
Convergent Boundary: Plates collide, old crust is destroyed. Examples include ocean-continent
collision, such as the Cascade Ranges and the Andes in South America; ocean-ocean collision,
such as the Japanese islands and Indonesia; and continent-continent collision, such as the
Himalayas.
Transform Boundary: Crust is neither created nor destroyed, horizontal displacement. An
example is the San Andreas Fault.
4. Why does oceanic lithosphere almost always sink beneath continental lithosphere at convergent
zones?
Answer:
Oceanic lithosphere is denser/heavier than continental lithosphere because it contains more iron-
and magnesium-rich minerals.
5. Along which type(s) of lithospheric plate boundary are large earthquakes common? Why?
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Chapter 2: Plate Tectonics and Physical Hazards
Answer:
Although earthquakes occur at all plate boundaries, convergent boundaries produce the largest
earthquakes. As one plate is being subducted beneath another, the overlying crust deforms.
Eventually the stress applied to the rock is greater than the strength of the rock, causing the crust
to fracture.
6. Along which type(s) of lithospheric plate boundary are large volcanoes most common? Provide
an example.
Answer:
Continent–ocean convergent boundary (Cascadia subduction zone/High Cascades volcanoes)
and ocean-ocean convergent boundary (Japanese islands).
7. What direction is the Pacific Plate currently moving, based on FIGURE 2-15? How fast is this
plate moving?
Answer:
West-northwest; approximately 9 cm per year.
8. Before people understood plate tectonics, what evidence led some scientists to believe in
continental drift?
Answer:
Geographic fit of continents by matching coastlines across the Atlantic Ocean, match of rock
formations across the Atlantic Ocean, match of ages of continental rocks across the Atlantic
Ocean, match of fossils across the Atlantic Ocean, and glacial patterns.
9. If the coastlines across the Atlantic Ocean are spreading apart, why isn’t the Atlantic Ocean
deepest in its center?
Answer:
New ocean floor wells up and forms a ridge in the middle of the Atlantic Ocean (Mid-Atlantic
Ridge).
10. What evidence confirmed seafloor spreading?
Answer:
Reversals of the Earth’s magnetic field are preserved in ocean-floor basalt, as matching patterns
across the mid-oceanic ridge. The youngest ocean-floor basalt is at the ridge.
11. Why are high volcanoes such as the Cascades found on the continents and in a row parallel to
the continental margin?
Answer:
They are the surface expression of the active subduction zone.
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Chapter 2: Plate Tectonics and Physical Hazards
12. Explain how the modern theory of plate tectonics developed in the context of the scientific
method.
Answer:
The scientific method is based on logical analysis of data to solve problems. The evidence for
continental drift and additional data such as magnetic patterns in the ocean floor were used to
test the hypothesis of plate tectonics.
13. How does the height of a mountain range compare with the thickness of the crust or lithosphere
below the mountain? Relate this to the percentage of an iceberg above the water line.
Answer:
The height of an iceberg above the water line or a mountain range above the average continent is
dependent on the difference in density between the submerged part of the iceberg or mountain
and the surrounding water or mantle. Because the density of ice is 90% of the density of the
surrounding water, 10% of the iceberg is above the water. The density of average continental
rocks is 84% of the density of the mantle. This results in 16% of the mountain being exposed.
ANSWERS TO CRITICAL THINKING QUESTIONS
1. Explain the role of Earth material densities with respect to Earth’s features such as mountains
and mid-oceanic ridges. For example, why is the top of basaltic crust below sea level while the
surface of granitic crust is generally above sea level?
Answer:
The role of Earth material densities in shaping features like mountains and mid-oceanic ridges is
significant. For instance, the top of basaltic crust is below sea level because it is denser, while the
surface of granitic crust is generally above sea level due to its lower density. This phenomenon is
explained by isostasy, where the less dense continental crust floats higher on the denser mantle,
while the thinner oceanic crust sinks lower. Major mountain ranges often have deep roots with
thicker crust compared to adjacent areas, indicating subduction of denser oceanic crust beneath
a lighter continental crust. This subduction process, driven by plate tectonics and seafloor
spreading, results in volcanic activity and earthquakes, ultimately shaping Earth's topography.
2. The Basin and Range region of Nevada and Utah is a continental spreading zone. Because it is
pulling apart, why isn’t its elevation low, rather than as high as it is? Why isn’t it an ocean?
Answer:
The Basin and Range region of Nevada and Utah, despite undergoing continental spreading,
does not have a low elevation as one might expect. This is because the spreading occurs at a
slow rate, preventing the land from sinking to form a lower elevation. Additionally, the region
cannot split the continental plate quickly enough to create a new ocean floor, so it does not
become an ocean. Therefore, its elevation remains relatively high, and it retains its continental
character.
3. The scientific community initially rejected Wegener’s hypothesis of continental drift and remained
skeptical for decades. Does skepticism help or hinder scientific progress?
Answer:
Skepticism initially hindered scientific progress regarding Wegener’s hypothesis of continental
drift. Many scientists rejected his theory because they believed the proposed mechanism was
physically impossible. However, this skepticism prompted further investigation and the
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publicly accessible website, in whole or in part.
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Chapter 2: Plate Tectonics and Physical Hazards
development of alternative hypotheses. Eventually, Harry Hess proposed the idea of ocean floors
acting as giant conveyor belts, which laid the foundation for the modern theory of plate tectonics.
Thus, while skepticism initially slowed progress, it ultimately contributed to scientific advancement
by prompting critical analysis and the development of more accurate theories.
4. In formal scientific usage, hypothesis often indicates a tentative conclusion, whereas a scientific
theory is based on evidence tested over a long time and is considered to be scientific fact. What
other scientific issues have caused broad debate in social and political culture? Are they well-
supported scientific theories or just hypotheses?
Answer:
Students’ answers will vary depending on the source selected. In addition to the hypothesis-
theory distinction, debates in social and political realms often surround topics like climate change,
genetically modified organisms (GMOs), and vaccinations. While supported by substantial
evidence, they encounter resistance and controversy. Climate change is supported by
overwhelming scientific consensus. GMO safety is generally affirmed, though specific
applications raise concerns. Vaccinations are backed by extensive research, but skepticism
persists, challenging their acceptance as established scientific fact.
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