Understanding Volcanoes

What percentage of the planet's volcanoes are contained within the Ring of Fire?

• About 30%

• About 75%

• About 50%

• About 85%

What is magma referred to once it reaches above ground?

• Rock

• Ash

• Crust

• Lava

Which type of volcano is characterized as tall and steep?

• Shield volcanoes

• Stratovolcanoes

• Mid-ocean ridges

• Calderas

What is the primary cause of volcanic eruptions?

• Magma escaping through vents in the Earth's crust

• Sudden cooling of the Earth's core

• Oceanic water pressure

• Lightning strikes

What is the VEI scale used for?

• To measure and classify the explosivity of eruptions

• To measure the depth of a volcano

• To classify the types of lava

• To determine the age of a volcano

What can reach temperatures of over 2000 degrees Fahrenheit?

• Lava

• Volcanic ash

• The Earth's core

• Ocean water near a volcano

Which type of volcanic feature is a large depression in the ground?

• Calderas

• Shield volcanoes

• Stratovolcanoes

• Mid-ocean ridges

What catastrophic event occurred in Indonesia in 1815?

• The eruption of Krakatoa

• A large tsunami

• The eruption of Mount Tambora

• A massive earthquake

What is the effect of pyroclastic flow?

• It cools the lava instantly

• It forms new volcanic islands

• It can race down the sides of a volcano burning everything in its path

• It increases the fertility of the soil immediately

What natural benefit do volcanoes provide to the Earth?

• They reduce carbon dioxide levels

• They make the land fertile through volcanic ash

• They decrease the temperature of the planet

• They increase the oxygen level in the atmosphere