Chapter 5 Reading Quiz E1

How is this chain of volcanic islands forming?

A tectonic plate is moving over a mantle plume, which burns through the plate to create a chain of volcanoes.

Match the following pyroclastic materials in order from smallest to largest.

Ash- smallest Lapilli- Neither smallest nor largest Volcanic bombs- largest

Which of the following lavas make up 90 percent of the total volume of lava on Earth?

Basaltic

Using the choices below, select the statement that best explains how dissolved gases drive volcanic eruptions.

Confining pressure decreases on a rising magma, allowing gas bubbles to expand and fracture the magma. This process further decreases pressure on the magma and will result in an explosive event.

Along which tectonic boundary would the greatest amount of magma be generated every year? Why?

Divergent boundaries: magma produced by decompression melting

Most cinder cones have eruptive phases that last for centuries.

False

The more the silica in magma, the lower the viscosity.

False

How is magma generated along subduction zones?

Fluids are dehydrated out of the descending plate, which lowers the melting point of the surrounding mantle.

What is the driving force behind pyroclastic flows?

Gravity

Around which volcano is a scientist likely find pillow basalts?

Kilauea

The ring of fire is a narrow zone of composite cone volcanoes rimming the ________ Ocean.

Pacific

Match the volcanic hazard with its definition.

Pyroclastic flow- hot, fast-moving body of expanding gas and ash that hugs the flanks of the volcano. Lahar- fluid mudflow of volcanic debris. Tsunami- destructive sea wave triggered by powerful explosions or landslides into large bodies of water. Ash Falls- large volumes of ash precipitating from eruption cloud. Volcanic Gases- substances like CO2, SO2, Cl, and F that can result in climate change and be hazardous to human health.

Based on the volcanic type and construction of the flanks, what assumptions can you make about the type of lava?

The lava is basaltic

Based on the volcanic type and construction of the flanks, what assumptions can you make about the viscosity of the lava?

The lava is low viscosity

An example of a volcanic caldera that formed from the collapse of a magma chamber after large volumes of material were erupted is ________.

Yellowstone

Which of the following would decrease the viscosity of magma?

an increase in temperature

What type of lava is produced at a divergent plate boundary?

basaltic

What kind of volcano is most closely associated with pyroclastic flows?

composite cones

Along which tectonic boundary will chains of composite cone volcanoes be located?

convergent boundaries

Most magma on Earth is produced at ___ plate boundaries.

divergent

GPS units, satellites, and lasers are some of the tools used to monitor the ________ of the volcanic flanks, which indicates magma accumulating in the magma chamber.

inflation

Kilauea is a volcano created by ________.

intraplate volcanism

What kind of viscosity would flood basalts have?

low viscosity

What kind of volcanic hazard can be triggered by the collapse of a lava dome?

pyroclastic flows

With the exception of volcanoes associated with a subduction zone, most volcanic islands are ________ volcanoes.

shield

What kind of volcano is this?

shield volcano (have a shallow magma chamber)

Which volcanic type(s) can have pyroclastic ejections during eruptions?

shield volcanoes, cinder cones and composite cones

Lavas erupting from composite cones are generally ________-rich, making them very viscous.

silica

________ is a material's resistance to flowing.

viscosity