Deck 5: Volcanoes and Volcanism

Question 1

The three major types of volcanoes are ____.

A)shield volcanoes, cinder cones, and lava domes
B)shield volcanoes, cinder cones, and composite volcanoes
C)cinder cones, composite volcanoes, and lava domes
D)composite volcanoes, stratovolcanoes, and lava domes
E)shield volcanoes, composite volcanoes, and stratovolcanoes

Answer 1

shield volcanoes, cinder cones, and composite volcanoes

Question 2

Some lava flows show a pattern of columns bounded by fractures. These columns are usually ____-sided.

A)three
B)six
C)eight
D)twelve
E)twenty

Answer 2

six

Question 3

Fissure eruptions result in shield volcanoes.

Answer 3

False

Question 4

An extinct volcano ____.

A)existed during a past geological period and cannot be detected by humans
B)has not erupted during historic time, but may do so again
C)is the same thing as a dormant volcano
D)has not erupted during historic time and shows no sign of doing so in the future
E)can only be detected with specialized equipment

Question 5

A volcano that has not erupted within the last 1,000 years is classified as extinct.

Question 6

Other than Earth, what planet is most likely to have active volcanoes?

A)Mercury
B)Venus
C)Mars
D)Saturn
E)Neptune

Question 7

Geologists successfully gave timely warnings of impending eruptions of Mount St. Helens and Mount Pinatubo.

Question 8

The relatively small eruptions of the Icelandic volcano Eyjafjallajokull in 2010 caused major disruptions because the eruptions ____.

A)were pyroclastic and debris was thrown as far as three kilometers
B)occurred in a densely populated area
C)caused tsunamis and disrupted sea trade
D)took place beneath a glacier resulting in steam explosions that disrupted air traffic for several days
E)caused shallow earthquakes that caused landslides and destroyed buildings

Question 9

Most scientists believe that volcanism has played a major role in the depletion of the ozone layer in Earth's stratosphere.

Question 10

Harmonic tremor indicates that magma is moving beneath a volcano.

Question 11

Volcanic bombs have a twisted, streamlined shape, which indicates that they ____.

A)cooled quickly underwater
B)were formed from ropy, viscous mafic flows
C)were erupted as globs of magma that cooled and solidified during their flight through the air
D)have high amounts of dissolved gases and low amounts of sodium
E)were erupted gently from a shield volcano and cooled as they moved downslope

Question 12

In 1986, in Cameroon, many people died when an explosive cloud of carbon dioxide engulfed them. However, carbon dioxide emitted from volcanic activity is usually no problem because it dissipates quickly in the atmosphere.

Question 13

After a volcano erupts, the frequency of its future eruptions follow a very predictable pattern.

Question 14

Columnar jointing in lava flows occurs due to ____.

A)pyroclastic welding
B)basaltic crystal formation
C)contact of the lava flow with sea water
D)the expansion of lava flow materials
E)cooling and contracting of lava flows

Question 15

Not all volcanism results in the origin of volcanoes.

Question 16

Pillow lava forms when ____.

A)lava is rapidly chilled underwater
B)lava cools slowly on land
C)pyroclastic volcanic ash is consolidated
D)lava is ejected from a lava tube
E)a pahoehoe flow cools and becomes an aa flow

Question 17

Although it is difficult to get a precise number of active volcanoes, a common estimate is about ____.

A)100
B)250
C)550
D)1100
E)2000

Question 18

A nuée ardente is composed of fiery hot gases and dust.

Question 19

The dominant gas emitted from volcanoes is ____.

A)water vapor
B)carbon dioxide
C)sulfur dioxide
D)hydrogen fluoride
E)carbon monoxide

Question 20

Earth is the most volcanically active body in our solar system.

Question 21

Calderas are formed when ____.

A)low-viscosity magma flows out into very large areas and cools
B)pyroclastic flows mix with lava flows
C)the volcanic pipe is plugged and the increase in pressure causes a huge explosion
D)part of a magma chamber drains and the mountain's summit collapses into the vacated space below
E)large explosions at the base of a volcano cause the volcano to collapse

Question 22

What are the criteria used by geologists to give a semiquantitative measure of the size of an eruption?

A)number of deaths caused by the eruption and the number of buildings destroyed
B)volume of material erupted and height of the eruption plume
C)size of the pre-erupted volcano and the type
D)temperature and pressure during eruption
E)sizes of pyroclastic materials ejected and the distances they travel from the volcano

Question 23

A dense cloud of pyroclastic materials and a glowing cloud of gases and dust is called a(n)____.

A)nuée ardente
B)ash cloud
C)eruptive blast
D)mantle plume
E)fumerole

Question 24

At convergent plate boundaries, more viscous magmas, usually of felsic composition, are emplaced as ____, thus accounting for the explosive eruptions that typically occur there.

A)supervolcanoes
B)plutons
C)fissures
D)lava domes
E)cinder cones

Question 25

Basalt plateaus erupt from ____.

A)supervolcanoes
B)shield volcanoes
C)fissures
D)lava domes
E)cinder cones

Question 26

Cinder cones ____.

A)are large, gently sloped volcanoes
B)often form on the flanks or within the calderas of larger volcanoes
C)are often formed during the beginning stages of volcanic activity
D)are also called stratovolcanoes
E)result from the buildup of many layers of ancient lava flows

Question 27

Lava domes form from ____.

A)mafic and intermediate magma
B)intermediate magma
C)viscous felsic and intermediate magma
D)pyroclastic materials
E)fissure eruptions

Question 28

Nearly all remaining active volcanoes ____.

A)are at or near mid-oceanic ridges or the extensions of these ridges onto land
B)erupt approximately every 2,000 years
C)form pyroclastic sheet deposits
D)produce supervolcano eruptions
E)are located on the Eurasian plate

Question 29

The Hawaiian islands formed via ____ volcanism.

A)subduction zone
B)intraplate
C)divergent
D)convergent
E)lateral zone

Question 30

The volcanic explosivity index (VEI)____.

A)describes the characteristic shape of volcanoes
B)can be used to forecast eruptions
C)prevents fatalities and property damage
D)documents the size of eruptions
E)indicates whether a volcano produced a lava flow or a pyroclastic flow

Question 31

Many of the volcanoes in mainland Alaska and the Aleutian Islands ____.

A)are in the Cascade Range
B)were formed over hot spots
C)were formed over divergent plate boundaries
D)have formed within the last 1000 years
E)are composite volcanoes

Question 32

Where are most volcanoes located?

A)the Mediterranean belt
B)the mid-oceanic ridges
C)the circum-Pacific belt
D)the East African Rift Zone
E)Indonesia

Question 33

Pyroclastic materials ____.

A)have low viscosity and a ropy texture
B)are rare to absent at great depths in the ocean
C)do not vary in size
D)are always ejected very quickly from volcanoes
E)can only be found at locations where intraplate volcanism occurs

Question 34

A lahar may form when ____.

A)lava is cooled quickly underwater
B)volcanic gas is erupted into the stratosphere
C)lava cools and cracks along joints
D)magma moves through fissures in the country rock
E)rain falls on unconsolidated pyroclastic materials

Question 35

____ in California is the world's largest lava dome.

A)Mount Rainier
B)Mount Vesuvius
C)Mount Pinatubo
D)Mauna Loa
E)Lassen Peak

Question 36

Most of the world's active volcanoes are ____.

A)in South America
B)randomly distributed
C)currently erupting
D)in well-defined zones
E)the result of hot spot volcanism

Question 37

All volcanoes ____.

A)fall into one of five very distinct categories
B)display both lava flows and pyroclastic flows
C)form on either a convergent or a divergent plate boundary
D)have a conduit leading to a magma chamber beneath the surface
E)erupt on very short notice, making it difficult for people to prepare

Question 38

Most volcanism at spreading ridges goes undetected because it ____.

A)is so rare
B)occurs on the ocean floor
C)occurs deep within plutons
D)occurs deep in subduction zones
E)cannot be differentiated from other Earth processes

Question 39

A ____ is a type of volcano that has a steep-sided slope near its summit but a decreasing slope toward the base.

A)shield volcano
B)cinder cone
C)fissure volcano
D)composite volcano
E)lava dome

Question 40

Most of the approximately 3,300 historic eruptions lasted ____.

A)a few days
B)from less than one month to six months
C)one to two years
D)more than two years
E)more than 20 years

Question 41

Why are there volcanoes on the west coast of North America but not on the east coast?

Question 42

Erupting volcanoes eject pyroclastic materials of varying diameters. These materials, from smallest to largest are ____________________, ____________________, ____________________, and ____________________.

Question 43

Discuss what volcanologists look for when trying to determine if a volcano is about to erupt.

Question 44

The one place on Earth where mid-ocean ridge volcanism occurs above sea level is ____________________.

Question 45

Mount ____________________ erupted in 79 A.D. and buried the Italian city of Pompeii.

Question 46

The type of volcano with the gentlest slope is the ____________________ volcano.

Question 47

Compare and contrast fissure eruptions and pyroclastic sheet deposits.

Question 48

In highly viscous, felsic magma, if expansion is inhibited and gas pressure increases. Eventually, the pressure may become great enough to cause a(n)____________________.

Question 49

Briefly describe cinder cones.

Question 50

What are lava domes? Provide one example. Explain under what circumstances they form and what type of magma is usually involved? Are their eruptions gentle or violent?

Question 51

Define volcanism.

Question 52

Composite volcanoes are also known as ____________________ and are composed of both lava flows and ____________________ material.

Question 53

Would you rather be chased by a pahoehoe flow or an aa flow? Explain.

Question 54

Mafic magma is generated beneath spreading ridges, and intermediate or felsic magma forms where an oceanic plate is subducted beneath another plate. Therefore, we can conclude that most volcanism takes place at or near ____________________ and ____________________ plate boundaries.

Question 55

The particularly cold summer of 1816 was attributed to the huge eruption of Tambora in 1815 in Indonesia. In North America, 1816 was called ____________________.

Question 56

Erupting shield volcanoes are rather ____________________ compared with the eruptions of those at convergent plate boundaries.

Question 57

Sometimes tiny pyroclastic particles are ejected into the atmosphere and settle to the surface as a(n)____________________. In contrast, a(n)____________________ is a cloud of these tiny particles and gas that moves along or close to the land surface.

Question 58

Volcanic eruptions destroy buildings and productive land, and cause injuries and fatalities to life. Why, then, is volcanism considered a constructive process?