U4L5 Reading Volcanoes Quiz

What is the purpose of magma chambers in the Earth's crust?

• To store minerals

• To accumulate magma before it erupts

• To generate electricity

• To support plant life

Answer explanation

Magma chambers serve to accumulate magma beneath the Earth's surface before it erupts. This storage allows for pressure build-up, leading to volcanic eruptions when the magma eventually escapes.

What are hot spots related to?

• Oceanic ridges

• Mantle plumes

• Continental rifts

• Subduction zones

Answer explanation

Hot spots are primarily related to mantle plumes, which are columns of hot magma rising from deep within the Earth. These plumes can create volcanic activity at the surface, independent of tectonic plate boundaries.

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NGSS.HS-ESS2-1

NGSS.HS-ESS2-3

What happens to lava once it is in the air during an explosive eruption?

• It evaporates

• It solidifies and forms ashes

• It turns into water

• It disappears

Answer explanation

During an explosive eruption, lava that is ejected into the air cools rapidly and solidifies, forming tiny particles known as ash. This process prevents the lava from remaining in liquid form.

Which materials contribute to the structure of a composite volcano?

• Exclusively lava flows

• Exclusively volcanic ash

• Alternating layers of lava flows and pyroclastic deposits

• Only volcanic gases

Answer explanation

Composite volcanoes are formed from alternating layers of lava flows and pyroclastic deposits, which create their characteristic shape. This layering results from different eruption styles, making this choice correct.

What forms when magma intrudes into the cracks between the layers of rock and hardens within?

• Magmatic dike

• Sill

• Volcanic plug

• Lava flow

Answer explanation

When magma intrudes into cracks between rock layers and solidifies, it forms a magmatic dike. This structure is vertical or steeply inclined, distinguishing it from a sill, which forms horizontally between layers.

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NGSS.MS-ESS1-4

What temperature can a pyroclastic flow reach?

• 1,000 °C

• 100 °C

• 500 °C

• 50 °C

Answer explanation

A pyroclastic flow can reach temperatures of up to 1,000 °C, making it extremely dangerous. The other options, 100 °C, 500 °C, and 50 °C, are significantly lower than the actual temperatures observed in such flows.

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What is lahar?

• A type of volcanic rock

• A mixture of water, ice, debris, and ash

• A type of volcanic gas

• A type of volcanic eruption

Answer explanation

A lahar is a destructive volcanic mudflow that consists of a mixture of water, ice, debris, and ash. This makes the second choice the correct answer, as it accurately describes the composition of a lahar.

Tags

NGSS.MS-ESS3-2

Which indicators do scientists observe to predict a volcanic eruption?

• Seismic activity

• Cloud formations

• Wind speed

• Soil erosion

Answer explanation

Scientists monitor seismic activity, as increased earthquakes often indicate magma movement, a precursor to volcanic eruptions. Other options like cloud formations and wind speed are not reliable indicators of eruptions.

Tags

NGSS.MS-ESS3-2

What is a sign that an eruption may be nearing?

• Decrease in gas release

• Increase in gas release

• Change in wind direction

• Sudden rainfall

Answer explanation

An increase in gas release is a key indicator that an eruption may be nearing, as it suggests rising magma and pressure within the volcano. In contrast, a decrease in gas release would indicate stability.

Tags

NGSS.MS-ESS3-2

What is magma called when it reaches the surface of Earth?

• Lava

• viscosity

• toxic gas

Tags

NGSS.MS-ESS2-1