chapter 6 quiz

The typical form for a composite volcano is a

steep-sided cone.

What event triggered the main eruption of May 1980?

A landslide removed rocks and released pressure on the magma.

Which of the following are ways that viscosity affects gases in magma?

Viscous magma prevents gas from escaping easily.

A volcanic eruption occurring beneath an ice sheet is likely to cause

a flood

The type of volcanic eruption shown in this photograph is

a pyroclastic column.

Some scientists think that Yellowstone could cause a future disaster because

all of these

Which of the following are true of felsic magmas?

all of these

Composite volcanoes are so called because they

are composed of lava flows, pyroclastic material, and mudflows.

If bubbles cannot escape easily from a magma, the resulting eruption is likely to:

be explosve

Continental mantle plumes that are composed of felsic magma tend to be explosive when the Earth's surface is reached. These explosive eruptions create:

calderas

The main cause of caldera collapse is

collapse of the roof of a magma chamber as magma erupts.

The most dangerous type of volcano is a

composite volcano

Which of the following plate boundaries is least likely to produce composite volcanoes?

continent-continent convergent boundary with a high mountain range (Himalayas)

When two plates are moving away from each other they are said to be:

diverging

Shield volcanoes commonly involve

fluid lava flows

When basaltic lava reach the ocean they

form pillow basalts.

Volcanic mudflows (lahars) are common on composite volcanoes because

large amounts of rain and snowmelt mix with loose ash on steep slopes.

Which of the following settings is most likely to have eruptions of basalt?

mid ocean ridge

What tectonic setting is interpreted to be the cause of volcanism at Yellowstone?

movement of North America over a mantle plume

When a volcano erodes and the solidified conduit is exposed, it is referred to as a volcanic:

neck

Shield volcanoes are built up primarily by relatively

nonxplosive outpourings of lava

These photographs show different types of eruptions. Drag the name of the eruption type to the correct photograph.

obvious

What type of basaltic feature is shown in this photograph? Black lava

pahoehoe lava flow

Rocks of the continental crust contain different minerals and each mineral has its own melting point. If the minerals with the lowest melting temperatures are the only ones melted, this is referred to as:

partial melting

Which of the following materials is NOT produced by erupting volcanoes?

sandstone

This volcano is relatively small and composed of volcanic cinders. What kind of volcano is it?

scoria cone

Volcanic domes grow from lava being injected into the interior of mounds of cooled lava and from the breaking out and moving down the flanks of

viscious lava flows

What type of basaltic feature is shown in this photograph?

volcanic bomb