Geological Hazard

What is the primary cause of a volcanic eruption?

• The buildup of pressure from magma.

• Lava cooling rapidly in the air.

• Earthquakes causing ground shifts.

• Heavy rainfall eroding volcanic rock.

Which of the following gases is commonly released during a volcanic eruption?

• oxygen

• carbon dioxide

• nitrogen

• sulfur dioxide

What determines the viscosity (thickness) of magma in a volcano?

• The chemical composition, especially silica content, temperature, and gas content determine the viscosity of magma.

• The type of rock surrounding the magma

• The age of the volcano

• The altitude of the volcano

What is the term used for solid material, such as ash and pumice, that is ejected during a volcanic eruption?

• Lava

• Tephra

• Volcanic gas

• Magma

Which type of lava is thicker and more likely to cause an explosive eruption?

• Pumice lava

• Andesitic or rhyolitic lava

• Basaltic lava

• Obsidian lava

What is the main cause of most landslides?

• Gravity and destabilization of soil and rock.

• Volcanic eruptions

• Heavy rainfall and flooding

• Earthquake vibrations

What type of volcanic eruption is characterized by the flow of lava?

• Phreatomagmatic eruption

• Explosive eruption

• Effusive eruption

• Plinian eruption

Which layer of the Earth is primarily responsible for volcanic activity?

• Crust

• Mantle

• Atmosphere

• Core

What is the name of the opening in the Earth's crust through which lava erupts?

• fault line

• geyser

• crater

• volcano

What is the difference between magma and lava?

• Magma is always found on the surface; lava is found underground.

• Magma is underground molten rock; lava is magma that has erupted onto the surface.

• Magma and lava are the same substance regardless of location.

• Lava is a solid rock; magma is a liquid rock.