Question 1

A ______ is a volcano constructed of pyroclastic fragments ejected from a central vent.
A) shield volcano
B) caldera
C) stratovolcano
D) dome
E) cinder cone

Accepted Answer

A cinder cone is a small, steep-sided volcano that is constructed of pyroclastic fragments (ash, cinders, and bombs) ejected from a single vent. It is a type of volcanic cone, also known as a scoria cone.

Question 2

In 1902 the port city of St. Pierre on the island of Martinique was destroyed by a ___.
A) tsunami
B) lava flow
C) mud flow
D) poison gas cloud
E) pyroclastic flow

Accepted Answer

St. Pierre was destroyed by a pyroclastic flow, which is a fast-moving, extremely hot and deadly mixture of ash, rock fragments, and gas that is expelled from a volcano during an eruption. The eruption was caused by the Mount Pelée volcano.

Question 3

A ________ igneous rock is one in which larger crystals are enclosed in a groundmass of much finer-grained material.
A) aphanitic
B) phaneritic
C) polyphonic
D) porphyritic
E) mylonitic

Accepted Answer

Porphyritic igneous rock has larger crystals enclosed in a groundmass of finer-grained material. Aphanitic igneous rock is fine-grained all throughout, phaneritic igneous rock has visible crystals throughout, polyphonic is not a type of igneous rock, and mylonitic igneous rock has undergone significant deformation.

Question 4

Individual layers of basalt lava may be divided into vertical columns called ______.
A) pahoehoe
B) columnar basalt
C) pillow structure
D) collapse structure
E) tuff

Accepted Answer

Individual layers of basalt lava cool and contract, causing them to fracture into vertical columns. These columns are called columnar basalt. The other choices are related to different types of volcanic features or structures.

Question 5

Most of the better known composite volcanoes on Earth are __.
A) in the mid-ocean ridge system
B) in the circum-Pacific belt
C) in the Mediterranean belt
D) All of the choices are correct.
E) All of the choices are correct, except in the Mediterranean belt.

Accepted Answer

The answer of Most of the better known composite volcanoes...

Question 6

Crater Lake is a volcanic feature of _____.
A) the Cascade Mountains
B) Hawaii
C) the Aleutian Islands
D) the Ouachita Mountains
E) Baja California

Accepted Answer

Crater Lake is located in the Cascade Mountains in southern Oregon.

Question 7

Over 34,000 people died as a result of the ______ generated by the eruption of Krakatoa in 1883.
A) tidal wave
B) suzuki
C) roller
D) tsunami
E) whitecap

Accepted Answer

The eruption of Krakatoa in 1883 caused a massive tsunami that resulted in the death of over 34,000 people. Tidal waves, suzukis, rollers, and whitecaps are all types of waves, but only a tsunami is capable of causing such widespread devastation.

Question 8

A _________ is a volcanic depression much larger than the original crater, formed when the volcano collapses into a vacated magma chamber.
A) vent
B) caldera
C) basin
D) ring dike
E) crater

Accepted Answer

A caldera is a large volcanic depression formed by the collapse of a volcano following the depletion of magma in the underlying magma chamber. This can occur gradually or rapidly, and can result in a depression much larger than the original crater. A vent is an opening in the Earth's surface that allows magma and gases to escape, a basin is a low-lying area where water and sediments collect, a ring dike is a circular intrusion of magma that can be seen when a volcano has been eroded, and a crater is a depressed area at the summit of a volcano.

Question 9

_____ describes the surface of a basalt flow with a jagged, rubble surface.
A) Pahoehoe
B) Aa
C) Haleakela
D) Poy
E) Pele's hair

Accepted Answer

Aa is a type of basalt flow that has a jagged, rubble surface. Pahoehoe has a smooth, ropey surface. Haleakela is a shield volcano in Hawaii. Poy is not a term used in geology. Pele's hair is a type of volcanic glass that has a stringy, hair-like appearance.

Question 10

_____ describes the surface of a basalt flow with a smooth ropy surface.
A) Pahoehoe
B) Aa
C) Haleakela
D) Poy
E) Pele's hair

Accepted Answer

Pahoehoe is the type of basalt flow that has a smooth and ropy surface. Aa, on the other hand, has a rough and jagged surface. Haleakela is a volcano in Hawaii, Poy is not a recognized term in geology, and Pele's hair is a type of volcanic glass that forms from lava fountains.

Question 11

_________ is a hill or mountain formed by the extrusion of lava or ejection of rock fragments from a vent.
A) Caldera
B) Flank eruption
C) Pillow lava
D) Volcano
E) Cinder cone

Accepted Answer

A volcano is a hill or mountain formed by the extrusion of lava or ejection of rock fragments from a vent. Caldera is a depression formed after a volcanic eruption, while flank eruption refers to an eruption that occurs on the side of a volcano. Pillow lava is lava that forms underwater or along the bottom of a body of water, and cinder cone is a volcanic cone made up of loose volcanic fragments called cinders.

Question 12

Several times in Earth's history, outpourings of magma covered many thousands of square kilometers in multiple flows called __.
A) pillow basalts
B) plateau basalts
C) rift basalts
D) sheet basalts
E) regional basalts

Accepted Answer

The term "plateau basalts" refers to extensive lava flows that cover large areas of land and form plateaus. This type of volcanic activity is associated with flood basalt eruptions.

Question 13

The largest pyroclasts are __.
A) ash and dust
B) bombs/blocks
C) cinders
D) lapillis
E) sand

Accepted Answer

Bombs/blocks are the largest pyroclasts, which can range in size from a few centimeters to several meters in diameter. Ash, dust, cinders, lapilli, and sand are smaller in size in comparison.

Question 14

The eruption of ______ is related to the fact that the North American plate is overriding a portion of the Pacific Ocean floor.
A) Fuji
B) Tamboro
C) Mount St. Helens
D) Mount Pelee
E) Mauna Loa

Accepted Answer

Mount St. Helens is located in the Cascadia subduction zone where the North American plate is overriding the Juan de Fuca plate (a portion of the Pacific Ocean floor), leading to volcanic activity.

Question 15

________ are cavities in extrusive rocks resulting from gas bubbles in the lava.
A) Phenocrysts
B) Pleochroic
C) Vesicles
D) Vascular
E) Holy

Accepted Answer

Vesicles are cavities in extrusive rocks resulting from gas bubbles in the lava.

Question 16

Radar images of which planet show a surface that is young and still volcanically active?
A) Mercury
B) Venus
C) Mars
D) Neptune
E) Saturn

Accepted Answer

Radar images of Venus show a surface that is relatively young and volcanically active. This is because the planet's thick atmosphere traps heat and increases surface temperatures, leading to volcanic activity.

Question 17

________ is a rock composed of fine-grained pyroclastic particles.
A) Tuff
B) Pumice
C) Scoria
D) Rhyolite
E) Obsidian

Accepted Answer

Tuff is composed of compacted and cemented volcanic ash and other pyroclastic particles. Pumice is a lightweight and porous volcanic rock, while scoria is a more coarse-grained volcanic rock that often contains larger vesicles. Rhyolite is a fine-grained volcanic rock that is chemically similar to granite, and obsidian is a volcanic glass.

Question 18

________ is a frothy volcanic glass with so much void space that it can actually float.
A) Obsidian
B) Sponge rock
C) Pumice
D) Lava
E) A floater

Accepted Answer

Pumice is a volcanic rock that has a porous and frothy texture due to the presence of trapped gas bubbles. These bubbles give pumice a very low density, which allows it to float on water. Obsidian, on the other hand, is a dense, hard, and smooth volcanic glass that does not have void space and cannot float. Sponge rock and A floater are not commonly used geological terms. Lava is molten rock that can solidify into various types of igneous rock depending on its composition, but it does not have the specific properties of pumice.

Question 19

_____ refers to a rock's appearance with respect to the size, shape, and arrangement of its grains or other constituents.
A) Crystallinity
B) Texture
C) Extrusiveness
D) Magma
E) Viscosity

Accepted Answer

Texture refers to the size, shape, and arrangement of a rock's grains or other constituents. Crystallinity refers to the degree to which a rock is composed of interlocking mineral crystals, while extrusiveness refers to the type of magma or lava that a rock formed from. Magma refers to molten rock beneath the Earth's surface, and viscosity refers to a substance's resistance to flow.

Question 20

A _________, a mixture of gas and volcanic debris, may blast out laterally under a viscous plug capping a volcano.
A) pyroclastic flow
B) mud flow
C) debris flow
D) lava flow
E) lahar

Accepted Answer

A pyroclastic flow is a mixture of gas and volcanic debris that can blast out laterally from a volcano, often under a thick, viscous plug. This mixture can move down slopes and valleys at extremely high speeds, making it one of the most dangerous volcanic hazards.

Quiz 4: Volcanism and Extrusive Rocks

A ______ is a volcano constructed of pyroclastic fragments ejected from a central vent.

In 1902 the port city of St. Pierre on the island of Martinique was destroyed by a ___.

A ________ igneous rock is one in which larger crystals are enclosed in a groundmass of much finer-grained material.

Individual layers of basalt lava may be divided into vertical columns called ______.

Most of the better known composite volcanoes on Earth are __.

Crater Lake is a volcanic feature of _____.

Over 34,000 people died as a result of the ______ generated by the eruption of Krakatoa in 1883.

A _________ is a volcanic depression much larger than the original crater, formed when the volcano collapses into a vacated magma chamber.

_____ describes the surface of a basalt flow with a jagged, rubble surface.

_____ describes the surface of a basalt flow with a smooth ropy surface.

_________ is a hill or mountain formed by the extrusion of lava or ejection of rock fragments from a vent.

Several times in Earth's history, outpourings of magma covered many thousands of square kilometers in multiple flows called __.

The largest pyroclasts are __.

The eruption of ______ is related to the fact that the North American plate is overriding a portion of the Pacific Ocean floor.

________ are cavities in extrusive rocks resulting from gas bubbles in the lava.

Radar images of which planet show a surface that is young and still volcanically active?

________ is a rock composed of fine-grained pyroclastic particles.

________ is a frothy volcanic glass with so much void space that it can actually float.

_____ refers to a rock's appearance with respect to the size, shape, and arrangement of its grains or other constituents.

A _________, a mixture of gas and volcanic debris, may blast out laterally under a viscous plug capping a volcano.