Deck 32: Volcanism and Its Landforms

Question 1

When a volcano appears inactive and shows signs of weathering and erosion along the surface, it is said to be:

A) active
B) dormant
C) extinct
D) quiescent

Answer 1

C

Question 2

All volcanoes occur on plate boundaries.

Answer 2

False

Question 3

The chain of explosive volcanoes that lie along the circumference of the Pacific Ocean is sometimes referred to as the:

A) circum-Pacific Arcs
B) Pacific Ring of Fire
C) island arcs
D) volcanic arcs

Answer 3

B

Question 4

Which factor determines whether a volcano will have an explosive, violent eruption?

A) the amount of dissolved oxygen
B) how long ago its last eruption occurrence
C) how high the temperature
D) the amount of magma in the volcanic chamber

Question 5

Which of the following has the highest magma viscosity?

A) high silica content (rhyolitic)
B) low silica content (basaltic)
C) high iron and magnesium content
D) none, all magma have the same viscosity

Question 6

The majority of continental and island-arc volcanoes are in or near:

A) spreading centers
B) transform boundaries
C) subduction zones
D) hot spots

Question 7

A type of volcano that erupts fluid basalt is called:

A) composite cones
B) calderas
C) lava domes
D) shield volcanoes

Question 8

Gases cannot escape from _____ magma easily; therefore, they produce _____ eruptions.

A) high-silica; effusive
B) high-silica; explosive
C) low-silica; explosive
D) none of the above

Question 9

Lahars may be caused by:

A) rapid snowmelt
B) intense rainfall
C) rapid shaking
D) both (a) and (b)

Question 10

Gases escape easily from low viscosity magma, causing pressure to remain stable. This produces a(n):

A) explosive volcano
B) effusive (quiet) eruptions
C) continuous lava flows
D) water vapor to escape

Question 11

As fluid basaltic lava pours out of linear cracks, or fissures, ___ form large sheets of lava rather than a typical cone-shaped volcano.

A) long, windy lava flows
B) sheet lavas
C) flood basalts
D) blanket lavas

Question 12

Calderas are elongated, circular depressions on Earth's surface that typically form by:

A) the emptying of a magma chamber and subsequent roof collapse
B) a gradual buildup of pyroclastic material around a volcanic vent
C) the impact of a meteor collision with Earth
D) a ring of volcanoes surrounding a depression

Question 13

Another name for a pyroclastic flow is:

A) lahar
B) mudflow
C) avalanche
D) nuee ardente

Question 14

Hawai'i, Yellowstone, and the Snake River Plain form on or near:

A) spreading centers
B) transform boundaries
C) hot spots
D) subduction zones

Question 15

It is difficult for scientists to understand the evolution of ancient volcanoes (stratovolcanoes). Many times researchers can determine the degree of explosiveness and the height of the eruption column by studying the size of pyroclastic material and the distance they travelled. It can be inferred that the larger the fragments erupted, the more explosive the eruption; the more explosive the eruption, the farther the distance volcanic fragments travel; and:

A) the thinner the ash deposits, the longer the duration
B) the farther pyroclastic material travel, the higher the eruption column
C) the thicker the pyroclastic deposit, the smaller the eruption column
D) the higher the volume of pyroclastic material erupted, the shorter the duration

Question 16

The Hawaiian Islands formed over a stationary hot spot. This means that hot molten magma from deep within the mantle erupted onto the surface of the ocean floor, forming an underwater volcano, or seamount. As the volcano continued to grow, it eventually emerged above sea level, forming an island arc. The first island to form over the hot spot was Kauai Island. The island sits at the northernmost section along the chain, is now an extinct volcano, and contains the oldest rocks of the Hawaiian Islands. Maui is also an extinct volcano. It has much younger rocks than Kauai but older than the Big Island. Hawai'i is the southernmost island, has active volcanoes, and contains the youngest rocks of all the islands. By understanding that the Hawaiian Islands formed over a stationary hot spot, the youngest rocks are found on the actively-erupting Hawai'i island, and that rocks become progressively older as you move northwest helps support what theory?

A) Plate Tectonics Theory
B) Continental Drift Theory
C) Ring of Fire Theory
D) Seafloor Spreading Theory