Earth Space Chapter 10 Test

A volcanic ___________ forms when the rock in a pipe is resistant to erosion and remains standing above the surface after the rest of the volcano has worn away.

neck

What is the most abundant gas associated with volcanic activity?

water vapor

Which of the following plays a major part in determining the form of a volcano?

magma composition

Structures that form from the cooling and hardening of magma beneath Earth's surface are

plutons

Which type of landform develops at plate boundaries where one oceanic plate descends beneath another?

rift valley

Explain a lava plateau.

A lava plateau is a volcanic landform produced by repeated eruptions of very fluid, basaltic lava.

What is a volcanic neck?

A volcanic neck is a landform made of magma that hardened in a volcano's pipe and later was exposed by erosion.

Compare aa to pahoehoe lava flow

AA is rough, jagged lava whereas pahoehoe lava is smooth and rope-like.

What type of volcano is made from layers of lava and pyroclastic deposits?

Composite cones

From least viscosity to greatest, put compositions in order (magma reference table)

Basaltic, Andesitic, Granitic

What type of volcano is built from ejected lava fragments?

Cinder cone

How can calderas form?

Most calderas form in one of two ways: by the collapse of the top of a composite volcano after an explosive eruption, or from the collapse of the top of a shield volcano after the magma chamber is drained.

Explain the formation of crater lake.

This caldera formed about 7,000 years ago when a composite cone, Mount Mazama, partly emptied the chamber. The roof of the magma chamber collapsed, forming a huge depression that became Crater Lake.

What type of volcano is fairly symmetrical and has both layers of lava and pyroclastic deposits?

a composite cone volcano

At divergent plate boundaries in the ocean, magma rises and melts because of

a decrease in pressure

What is a caldera?

a large depression in a volcano

What is a volcanic bomb?

a particle larger than 64 mm in size ejected as glowing lava

When a common type of basaltic lava hardens, it forms aa, which has

a rough, jagged surface

Which type of intrusive feature forms when magma is injected into fractures cutting across rock layers?

a sill

A lava flow with a surface of rough, jagged blocks and sharp, angular projections is called a(n)

aa flow

Why do volcanoes with very viscous magmas erupt the most explosively?

as magma moves upward, the volcano pressure decreases, releasing dissolved gases. more viscous magma attracts gases and they explode more violently

Large particles of hardened lava ejected from a volcano are called

blocks

Gases escaping from volcanoes often include _________________, _________________, nitrogen, and sulfur, with lesser amounts of chlorine, hydrogen, and argon.

carbon dioxide, water vapor

What type of volcano is built almost entirely from ejected lava fragments?

cinder cone

Which type of volcano will have the quietest type of eruption? Explain your answer.

cinder cone/ even shield, lava has low silica and gas content, fluid lava, low viscosity

the most explosive volcanic eruptions come from _________ volcanoes.

composite

What type of volcano is illustrated in Figure 10-1?

composite cone

A volcano that is fairly symmetrical and has both layers of lava and pyroclastic deposits is a

composite cone volcano

The broad, slightly dome-shaped volcanoes of Hawaii are

composite cone volcanoes

Where slabs of oceanic lithosphere are subducted under continental lithosphere, a _______________ volcanic arc can form.

continental

What feature is labeled D is Figure 10-1?

crater

Descending into Earth's interior, temperature, as well as pressure on a rock,

increases

Most shield volcanos have grown from the ocean floor to form

islands

As the temperature of lava increases,

ist viscosity decreases

Which of the following is NOT true of a batholith?

it is the largest intrusive igneous body

As the temperature of lava increases,

its viscosity decreases

Saturated volcanic debris that rapidly moves down steep, volcanic slopes as a mudflow is a(n) ________________.

lahar

A caldera is a

large depression in a volcano

Highly explosive volcanoes tend to have what type of magma?

magma with high silica, high viscosity, and higher gas content

Which of the following is NOT a factor in how violently or quietly a volcano erupts?

magma's temperature

What are the landforms at divergent ocean plate boundaries?

ocean trenches

Most intraplate volcanic activity occurs where

oceanic plates diverge

A(n) ___________ lava flow resembles the twisted braids in rope as it cools and hardens.

pahoehoe

Which of the following is not considered to be a pyroclastic material?

pahoehoe (ash, bombs, and blocks)

Magma forms when solid rock in the crust and upper mantle

partially melts

A volcanic bomb is a

piece of semi-molten rock ejected as glowing lava, a particle larger than 64 mm in size ejected as glowing lava

What feature is labeled A is figure 10-1?

pipe

The magma that feeds most volcanoes moves from a magma chamber towards the surface through ________________.

pipes

The particles produced in volcanic eruptions are called

pyroclastic material

The particles produced in volcanic eruptions are called

pyroclastic materials

Which list places the magma types in order of decreasing viscosity (most viscous listed first)?

rhyolitic, andesitic, basaltic

How do scientists classify intrusive igneous figures?

shape, size, relationship with surrounding rock layers

The accumulation of fluid basaltic lava produces a(n) ________________.

shield

The broad, slightly dome-shaped volcanoes of Hawaii are

shield volcanoes

Why are pyroclastic flows not associated with shield volcanoes?

shield volcanos have fluid lava and erupt quietly

Rhyolitic lavas are very viscous because they have a high __________ content.

silica

A magmas viscosity is directly related to its

silica content

Which of the following is similar to a batholith but has less than 100 square kilometers exposed?

sill

Which of the following is not a factor affecting how violently or quietly a volcano erupts?

size of the volcanos cone

Another name for a composite cone volcano is a(n) _________.

strato volcano

Lava plateaus form when

the fluid basaltic lava flows out of fissures

The volcanic landform that is formed when the more resistant volcanic pipe remains after most of the cone has been eroded is called a

volcanic neck