Salt Lake Community College - Geography 1700
Quiz #2 - Spring, 2015
A. J. Allred, Adjunct
Student Name: ____________________
1. Buildings that prevent injury to people during earthquakes tend to be made of solid, heavy masonry rather than
light-weight, flexible materials that are easily shaken.
True ___
False ___
Solid masonry tends to absorb energy rather than flexing to allow energy to flow through to somewhere else.
Heavy masonry tends to be brittle and may fall apart, sometimes even when steel reinforcing, such as rebar, has
been added. Falling masonry is a threat to people and property.
Much of the world’s population lives in buildings made of masonry, stone, mud, manure or other earth materials
that are unstable, especially when wet. As a result, earthquake casualties are sometimes vast. Across history,
millions of people have also lived in unstable caves, and many still do.
2. The 2011 ‘Fukushima’ catastrophe in Japan was started by an earthquake that produced tsunami waves as secondary
or indirect effects. A nuclear power plant was damaged and many forms of pollution resulted as well. In your
opinion, was the Fukushima event a natural disaster?
a.
b.
c.
d.
e.
Yes, Fukushima was a natural event. We can’t prevent these things, or event predict them.
No, Fukushima was man-made. There was no excuse for it.
Natural hazards can be understood. The real question is how to manage people and their mistakes.
I hate questions like this. Just tell me the answer.
All of the above all typical responses from people when disaster strikes.
The best answer covers the fact that people are partly right about almost anything they believe regarding natural
hazards.
Clearly, the Fukushima disaster was started by tectonic movement that can’t be predicted or even forecasted
reliably, even though it has been occurring for millions of years. Secondary and tertiary effects include:
1.
2.
3.
4.
5.
tsunami wave (natural)
human deaths and injuries
vast damage to property
loss of economic productivity
Particularly, all of Japan’s nuclear power plants have been shut down, and release of radioactive isotopes has
contaminated water, air and soil.
In my opinion, answer ‘c’ above is the best single answer, as a starting point for talking about how interwoven
people are with their environment.
The Japanese understood earthquake and tsunami hazards. They built a wall to protect the nuclear power plant from
dangerous waves. However, they did not understand that the shoreline itself would sink after the quake, making the
wall too short to stop the tsunami.
3. All hazards and disasters result from some form of nuclear energy. Humans live on Earth’s thin, brittle crust that
serves as a 'battle-ground' between solar fusion and tectonic heat. Water is the most important factor in turning
energy into hazards, and all living things require water for survival.
True ____
False ____
Tectonic force results from Earth heat that is produced by decay of radioactive elements deep within the mantle and
core. Meanwhile, solar energy results from fusion of hydrogen into helium. Those two forces sustain all life on
earth and set up most natural hazards.
Water is quickly able to absorb energy and/or convert energy into heat. Water in one form or another controls life
on Earth and is the primary substance that absorbs and releases energy in almost any form.
4. Earth’s crust is soft and flexible, while the underlying asthenosphere is rigid and inflexible. The result is
earthquakes that occur on the surface, causing hazards for everyone nearby.
True ____
False ____
The asthenosphere is mostly melted rock that can flow. By comparison, the earth’s surface crust is relatively dry
and rigid, allowing fractures to occur along plate boundaries and fault zones in reaction to the fluid asthenosphere
below.
Typically, earthquakes do not occur on the surface, but underground where stresses build up and release. Surface
waves (obviously) occur on the surface as a result of an earthquake, but are not a cause of quaking.
5. The modern Modified Mercalli system for earthquake reporting is fast enough to help predict the size, number
and timing of earthquake aftershocks. Foreshocks are not a reliable precursor for the main quake shock.
True ___
False ___
The Mercalli system is for post-event study, resulting in a gradually unfolding comprehensive picture of what
happened. The Mercalli system does not predict or prevent anything. Instead, it focuses on how seismic energy
affects people, property and landforms.
Mercalli reports may take weeks or months to prepare.
6. Human populations are growing in many of the world’s most quake-prone regions. To compensate for that trend,
buildings are now safer by having adopted uniform building codes, and by the universal use of standardized alert
systems and emergency response procedures.
True ___
False ___
The first statement is true. The second statement is not true. Humans have not compensated for population growth
by adoption of safe practices. As explained in class discussion, and found in references throughout the textbook,
building codes are often non-existent, out-of-date or ignored. Maintenance and repair are often behind schedule or
ignored. Alert systems are scattered, rather than universal, and many warning systems do not function well. In
many, if not most cases, the number of people exposed to natural hazards is probably greater than ever.
It takes a long time to convert new building science into . . . . new buildings. Most buildings are obsolete in regard
to seismic safety.
7.
An earthquake of M = 6.6 releases about how much more energy than a quake of M = 5.6?
a.
b.
c.
d.
e.
1.0 times more
3.2 times more
32.0 times more
Not enough information is provided to determine the Magnitude difference
All of the answers above are possible, based on whatever surface conditions exist.
For energy release, a quake of 6.6 is a full whole number larger than M 5.6, so 32 times more energy is released by
the larger quake. A change of 0.2 represents a doubling (or halving) or quake energy.
For shaking, a 10x scale is used, so a quake of M 6.6 would tend to cause about 10 times more shaking than a quake
of M 5.6.
8. The highest mountains on Earth (Himalaya) are being created by heavy, under-sea crust slowly sliding underneath
lighter continental crust.
True ___
False ___
The Himalyan mountains were created when the sub-continent of Indian moved northward and collided with Asia.
Both of these land masses are made of relatively lighter-weight crust. Neither one sub-ducted under the other.
Instead, during convergence, both plates have been rising, provoking unusually tall mountain uplifts.
9. Which of the following phenomena may suggest that the Earth has entered a new geologic epoch known as the
‘anthropocene’?
a. In recent years, ocean crusts have started subducting under dry continental crust
b. The existence of a billion automobiles, a billion belching cows, and 150,000 power plants
c. The ‘Ring of Fire’ that was created after human populations began to grow along the Pacific Rim in the
time period since World War II.
d. Terms like the ‘Anthropocene’ are invented by liberal politicians to create false alarms in order to control
human behavior.
e. All of the statements above are accurate.
The Pacific Rim “Ring of Fire” has existed for millions of years. Only recently has human population grown
substantially in that hazard zone. The rise of human activity has also resulted in vast changes to plants and
landforms on the surface of the earth.
The term “Anthropocene” suggests that the Earth’s surface has been altered so greatly by humans as to constitute a
major change in Earth history.
Political debate rages over how much humans are responsible for Earth climate and other natural events.
10. Inland urban centers like Salt Lake County are far enough away from ocean coasts to be safe from water waves
caused by earthquakes.
True ___
False ___
Salt Lake County is surrounded by lakes, rivers and underground water that can be affected by an earthquake. In
fact, in recent history, earth movement during quakes has caused hazardous water waves in many places far from
the ocean. In some cases, people have been killed and property damage has been severe.
Class discussion mentioned the possibility that even the Great Salt Lake might be induced to flood urban areas to
the east because of relatively flat terrain and block faulting that could produce an earthquake that allows the east
side of Salt Lake valley to drop.
Seismic waves in the ocean are called “tsunami” while in-land, fresh-water wave are usually called “seiche” waves.
11. If typical creep along a certain fault line totals about one inch per year then about how many years of “seismic
gap” would be relieved by an earthquake that suddenly moves that fault 10 feet?
a.
b.
c.
d.
e.
About a century
About 120 years
About 150 years
More than 200 years
About 10 to 12 years
A seismic gap represents a period of time during which tectonic tension or fault pressure is building, but not fully
released by creep or ‘slow quakes’. If the average, long-term rate of tectonic or fault movement is known, then the
amount of un-released movement during a seismic gap can be estimated, giving some idea of how big a quake
might someday occur.
For question #11 above, a quake that causes a 10-foot fault slip accomplishes as much as about 120 years of slow
creeping: One inch over 12 years produces 12 inches (one foot) of creep. A build-up of 10 feet of un-finished slip
would require 120 years at that same rate.
12. Which one of the following statements is true?
a. Utah is relatively less safe from earthquake damage than most of the United States because most buildings
in Utah are made of light-weight, wooden frames that shake easily during quaking.
b. Foreshocks are an important clue used by local public safety officials to prepare for a main quake shock.
c. Foreshocks are a type of quake precursor that helps form the basis for warning systems.
d. An earthquake of the “intra-plate” type is a serious threat to America’s Mississippi basin, in spite of not
producing a major quake in the past 200 years.
e. Answers ‘b’ and ‘c’ above are both true.
Foreshocks may not occur before a major quake, or may not be recorded or recognized before the main event. In
any case, there is no sure way of knowing if a foreshock is a precursor to an even larger event until the larger event
occurs. We also lack a confident basis for determining how much time will elapse between a foreshock, the major
quake, and various aftershocks.
13. Earthquakes and other tectonic forces often provide natural service functions that include scenic topography and
high terrain that collects water for farming.
True ___
False ___
Without tectonic activity, land surfaces would eventually wear down to flat, dusty surfaces covered by depleted
mineral resources. Tectonic forces create land forms and bring minerals to the surface. Solar forces tend to wear
everything back down.
High mountains often reach far enough into the sky to collect precipitation that might otherwise have fallen
somewhere else. Reservoirs and ground-water, along with winter snowpack then provide much-needed water for
dry places like Utah.
Recreation in mountains and in other terrain is a major human benefit from hazardous tectonic force.
14. Insurance policies and services, including government-funded programs ______________.
a.
b.
c.
d.
e.
tend to make people feel complacent and safe, with a false sense of security
may encourage unrealistic expectations for getting help when disaster strikes
do not stop the actual effects of natural events
require that everyone in the community help pay for the mistakes of a few people who did the wrong thing
All of the above are true of insurance programs.
As discussed in class, and throughout the textbook, human perception is a vital element in natural hazards and
losses. Insurance advertising emphasizes protection in the sense of providing replacement for losses, not in
prevention of losses. Having insurance does not prevent earthquakes, but provides limited compensation for
losses. Insurance does typically require qualification for insurability, but for the most part, insurance cannot
mitigate (as prevention) the effects of natural hazards. Insurance is more about replacement, and even provides
optional monetary values for human life.
The textbook will raise this issue a number of times in different chapters: government and private insurance, and
community relief services may cause people to feel less need to take responsibility for themselves, in advance of
natural events. Even building codes and land use planning regulations can create a perception that buildings are
safe, when in fact, codes and planning have only limited utility, and often don’t exist at all.
15. Which of the following applies to the term “mitigation”?
a.
b.
c.
d.
e.
Mitigation reduces the effect of an event or process.
Mitigation can replace you or your toys, but it really can’t protect you from actual events.
An ounce of prevention is worth a pound of cure
Mitigation is often boring and expensive, so we neglect working on it until it is too late.
All of the above help describe the term mitigation.
Mitigation can occur before, during or after a natural event. Ideally, we plan ahead to prevent problems, saving
lives and money. Still, we can’t prevent natural events or block all hazards, so emergency services are still vital
and post-disaster recovery will be a major activity for humans long into the future.