Magma Viscosity Factors Quiz

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What type of volcano is characterized by steep sides, a symmetrical cone shape, sticky lava, and alternating layers of lava flows, volcanic ash, and cinders?

Cinder cone volcano
Composite/Stratovolcano (correct)
Caldera volcano
Shield volcano

Which type of lava has the least explosive nature due to its low viscosity?

Andesitic lava
Rhyolitic lava
Dacitic lava
Basaltic lava (correct)

What are the roles of volcanoes in Earth's system according to the text?

Providing fertile soil through mineral-rich volcanic ash (correct)
Decreasing atmospheric oxygen levels
Creating deserts and arid landscapes
Causing global cooling by releasing greenhouse gases

Which volcanic region within a rigid plate is characterized by molten rock materials reaching the Earth's surface?

Hot Spot (A) Signup and view all the answers

What determines the nature of a volcanic eruption?

The viscosity of the magma (A) Signup and view all the answers

Which volcano type is described as having a broad, slightly domed shape and fluid basaltic lava?

Shield volcano (B) Signup and view all the answers

What effect does a higher temperature have on the viscosity of magma?

Decreases viscosity (D) Signup and view all the answers

How does the silica content of magma affect its viscosity?

Increases viscosity (A) Signup and view all the answers

What happens to the viscosity of magma with a higher amount of dissolved gases?

Decreases (A) Signup and view all the answers

Which type of magma is likely to result in an explosive eruption?

High viscosity magma (C) Signup and view all the answers

How does highly viscous magma affect the release of gas during an eruption?

Prevents gas release (D) Signup and view all the answers

What negative effects are associated with pyroclastic flows during a volcanic eruption?

Destruction of lives and properties (A) Signup and view all the answers

What is the difference between lava and magma?

Lava is magma that reaches the Earth's surface, while magma is molten rock found underneath the Earth's surface. (C) Signup and view all the answers

What causes magma to rise to the Earth's surface?

Magma being less dense than solid rocks and being squeezed by tectonic forces. (B) Signup and view all the answers

What is the main characteristic of dormant volcanoes?

They have not erupted in the last 10,000 years but are expected to erupt again in the future. (D) Signup and view all the answers

What type of volcanic vent emits gases only?

Fumarole (B) Signup and view all the answers

How is a caldera different from a crater?

A caldera is a basin-shaped depression formed when the volcanic cone collapses, while a crater is a funnel-shaped pit at the top of a volcanic vent. (C) Signup and view all the answers

Why does magma rise upward towards the Earth's surface?

As it is squeezed by tectonic forces and less dense than solid rocks. (A) Signup and view all the answers

Composite/Stratovolcano

A volcano with a steep, cone-shaped structure built up by alternating layers of lava flows, ash, and cinders.

Basaltic lava

Lava with low viscosity, meaning it flows easily and doesn't erupt explosively.

Volcanoes and Earth's Systems

Volcanoes contribute to Earth's systems by providing fertile soil through the release of mineral-rich ash.

Hot Spot

A region within a tectonic plate where molten rock, known as magma, rises to the surface, creating volcanoes.