Deck 7: Volcanoes Hazards and Mitigation

Question 1

The danger of volcanic ash is increased when ____.

A)it is composed of hydrogen sulfide compounds
B)the volcano creates rain, making building collapse more likely
C)dry conditions allow it to collapse quickly to form tuff
D)it contacts and melts snowbanks, resulting in flash floods
E)the flammable ash comes into contact with fire or high heat

Answer 1

B

Question 2

Volcanic losses to life and property ____.

A)depend on the eruption products and the population density near the volcano
B)have been decreased greatly by improvements in volcano prediction
C)were greater in prehistoric times than modern times
D)are greatest in developing countries and relatively minimal in developed countries
E)are effectively mitigated by barriers and other constructions

Answer 2

A

Question 3

A surge is a(n) ____.

A)upthrust in a lava dome
B)increase in pressure on a magma chamber
C)emission of poisonous gas
D)wave of steam associated with pyroclastic flows
E)increase in volcanic activity in a geographic area

Answer 3

D

Question 4

One of greatest threats from an explosion of Mount Rainier is mudflows in populated areas.

Question 5

The hazard posed by a volcano depends on both the population nearby and the eruption product.

Question 6

Barriers can be constructed to redirect volcanic mudflows.

Question 7

A volcano that has not erupted for over 10,000 years is not considered to be an active threat.

Question 8

Lava flows present one of the most significant volcanic dangers to human life.

Question 9

Mudflows move slowly enough that they present a danger to property but not to human life.

Question 10

Poisonous volcanic gasses can contaminate drinking water.

Question 11

Volcanic ash usually increases crop production after an eruption.

Question 12

Airplanes may experience risks from volcanic eruptions that cannot be anticipated.

Question 13

Historical records of volcanic eruptions ____.

A)are used effectively by land use planners and developers
B)cannot be used for prediction since volcanoes are inherently unpredictable
C)are effective in identifying areas at risk for volcanic dangers
D)are difficult to obtain since they depend on written history
E)are easily used to accurately predict the time of an eruption

Question 14

Volcanoes present a danger to aircraft ____.

A)that can be easily avoided since the danger builds slowly
B)due to the effect on the humans aboard the aircraft
C)due to the buildup of ash on propellers
D)due to the effect of the ash on jet engines
E)due to the corrosion of wing surfaces by volcanic gasses

Question 15

A pyroclastic flow cannot cross bodies of water.

Question 16

Lava flows ____.

A)move so slowly that they do not present a danger to either life or property
B)are often redirected by emergency efforts
C)can be redirected only with long-term planning and construction
D)move fast and are a threat to life and property
E)move slowly enough that they are usually a threat only to property

Question 17

The most dangerous poisonous gas(ses) associated with volcanic activity ____. ​

A)is hydrogen sulfide
B)are invisible but detectable by smell
C)must be breathed to cause damage
D)can weaken buildings by reacting to form sulfuric acid
E)can mix with moisture to make dangerous aerosols

Question 18

Pyroclastic flows ____.

A)can be protected against in the basement of structures
B)are rarely generated in volcanic eruptions
C)move slowly enough to be avoided
D)cannot move across bodies of water
E)can reach temperatures so hot that they glow

Question 19

Mudflows are a particular danger of ____.

A)cinder cone volcanoes
B)resurgent calderas
C)stratovolcanoes
D)shield volcanoes
E)lava domes

Question 20

Volcanic ash ____.

A)is so small that it does no damage if inhaled
B)is carried so high into the atmosphere that it does not have much effect on the area near an eruption
C)has a large effect near an eruption, but little effect further away
D)is composed of aerosols formed from the reaction of gasses and water vapor
E)is a major disruption to transportation and evacuation

Question 21

Any volcanic mud or debris flow is called a(n) _______________ by volcanologists.

Question 22

Warnings of volcanic mudflows ____.

A)are only possible at night when trained observers are available
B)can be effective only when GPS positioning is available
C)are difficult to act on because they leave little time to evacuate
D)cannot reach populations before the mudflow does
E)cause so many false alarms that they are often ignored

Question 23

The threat of volcanic disaster from volcanoes in the Pacific Cascades is less than for Mount Vesuvius because ____.

A)more accurate prediction and monitoring stations are in place ​
B)proper land-use planning has designated the areas around them as national parks
C)the population of the Pacific Northwest is better educated than the population of the Italian coast
D)local authorities have always responded proactively to volcano warnings
E)local tax codes have high penalties for building on sites of earlier volcanic damage

Question 24

Which statement about the danger of volcanoes in the Pacific Northwest is most accurate?

A)The Mt. St. Helens eruption of 1980 assures that the volcano will not be a threat for several decades.
B)Mt. Rainier poses a greater threat than other High Cascades volcanoes due to the large population living at its base.
C)Mt. Shasta is the most dangerous volcano in the region since it has not erupted in a long time.
D)Mt. Hood is very close to the Seattle-Tacoma metropolitan area and would destroy much of these cities in an eruption.
E)Mt. Baker has been the most frequent site of eruptions in the past and therefore is the greatest current danger.

Question 25

There has been some success demonstrated in controlling lava flows by using ____.

A)water to harden the leading edge of the flow
B)bulldozed trenches for the lava flow to follow
C)high explosives to disperse the lava over a wide area to cool
D)levees of older lava to funnel the flow into a valley
E)aerial bombing of the volcano caldera

Question 26

Harmonic tremors are ____.

A)strong earthquakes generated by an eruption
B)strong aftershocks generated after an eruption
C)the effect of magma dome collapse
D)weak earthquakes that precede an eruption
E)the effect of large gas emissions

Question 27

The predominant weather in the Pacific Northwest ____.

A)makes mudflows the most serious concern in eruptions
B)is likely to carry vog over major metropolitan areas
C)is not expected to increase the danger of volcanic damage
D)may interfere with evacuation and put more people at risk
E)is likely to increase the chance of pyroclastic flows

Question 28

The greatest clear danger posed by California's Mt. Shasta is ____.

A)gas emissions and swarms of small earthquakes, which indicate that an eruption is imminent
B)a hazard to shipping due to its close proximity to the ocean
C)the potential for huge landslides from slopes made of loose material covered by lava flows
D)pyroclastic flows threatening dozens of small towns built in nearby valleys on tuff
E)continuous seepage of carbon dioxide, which has killed thousands of trees and some hikers

Question 29

Ash eruptions form their own volcanic _______________ as rising ash plumes heat and lift surrounding air.

Question 30

The caldera now filled by Crater Lake

A)is the center of the Mazama resurgent caldera
B)formed as the top of the Mt. Mazama collapsed into the magma chamber after a major eruption
C)was formed in a titanic eruption that destroyed Mt. Mazama and blasted pieces of it over hundreds of square kilometers.
D)is the cooled vent formed when Mt. Mazama became an extinct volcano
E)prevents future eruptions by providing a way to cool rising magma

Question 31

Forecasts of the Mt. St. Helens eruption in 1980 were ____.

A)accurate about the force of the eruption, but not its timing
B)mostly incorrect, leading to mistrust by local authorities and residents
C)mostly correct, but were not acted on properly by authorities and residents
D)not made, because the proper technology had not been developed
E)correct, but did not reach local authorities in time to act on them

Question 32

Carbon dioxide ____.

A)is not dangerous due to its strong odor
B)is a danger in a volcanic area even when no eruption is imminent
C)tends to collect in the attic of houses when no eruption is imminent
D)is only a danger during periods of volcanic activity
E)is a particular danger to climbers and hikers since it is emitted at the summit of a volcano

Question 33

Which Italian city is dangerously located between two recently active volcanoes?

A)Rome
B)Milan
C)Naples
D)Venice
E)Sardinia

Question 34

Campi Flegrei, home to two million people, is a(n) ____.

A)extinct lava dome
B)active stratovolcano
C)extinct resurgent caldera
D)active resurgent caldera
E)active shield volcano

Question 35

Volcanic _______________ is composed of bits of pumice less than 2 mm across.

Question 36

The odorless, invisible gas that can be the most dangerous product of a volcano is ____.

A)hydrogen sulfide
B)carbon dioxide
C)carbon sulfide
D)sulfur dioxide
E)hydrogen dioxide

Question 37

When ash combines with water, it can form _______________ with a consistency of wet concrete

Question 38

A high-speed _______________ contains a high proportion of steam and advances in front of a pyroclastic flow.

Question 39

The town of Bend, Oregon ____.

A)is in the path of a mudflow from Mt. Rainier
B)is built on land from previous landslides from Mt. Shasta
C)was nearly destroyed by pyroclastic flows from Mt. St. Helens
D)is in danger of flooding if Mt. Mazama becomes active and ruptures the wall of Crater Lake
E)is next to an active bulging beside one of the Three Sisters volcanoes

Question 40

The geological study of rocks around a previously active volcano ____.

A)is of scientific interest but does not aid eruption prediction
B)is complicated by the effects of erosion
C)concentrates on the study of tuff layers, with little other useful information
D)can detect chemical changes in rocks caused by carbon dioxide emissions
E)can only identify sites of lava flows

Question 41

Discuss the particular dangers posed by volcanic hazards due to the Campi Flegrei in Italy.

Question 42

What differences in the danger due to volcanic ash would you identify for a home near Mt. Vesuvius versus one near Mt. Rainier? Consider only the effects of volcanic ash falling some distance from the volcano in your answer.

Question 43

After deposition, volcanic ash will form a rock called _______________.

Question 44

The prediction of volcanic danger based on volcanic activity during the prehistoric period relies on _______________-volcanology.

Question 45

Mount _______________ is a dangerous volcano in Italy that has a long history of threatening populations.

Question 46

Volcanic gasses and aerosols can create an acidic smog called _______________, which poses a threat to life and health.

Question 47

The _______________ Range is an area of particularly dangerous volcanoes in the United States.

Question 48

Explain the processes that lead to mudflows, and why they are hazardous to life and property.

Question 49

While on a visit to the Pacific Northwest you stop at Crater Lake, Oregon to enjoy the pristine beauty of the area. A friend traveling with you makes a comment that indicates that she thinks that the lake fills the solidified top of an extinct volcano. Educate your friend briefly using what you know about the area from the text.

Question 50

A friend of yours has built up a reputation in hospitality management and is an avid skier. Your friend is considering two equivalent job offers to manage services at ski resorts. One is in the town of Mt. Shasta, CA, 15 km SE of the peak of the mountain. The other is in Winter Park, CO, on the slope of the continental divide. Write a short email to your friend concerning factors from volcanic hazards only that may affect their decision.