Volcanic Eruptions and Igneous Rocks

What does viscosity refer to in the context of geology?

• The color of volcanic rocks

• The resistance to flow

• The temperature of magma

• The age of a volcano

Which factor does NOT influence the viscosity and type of volcanic eruption?

• Composition of magma

• Temperature of magma

• Amount of volatiles

• Age of the volcano

What is the relationship between the silica content of magma and the violence of the eruption?

• The more silica, the less violent the eruption

• The less silica, the more violent the eruption

• The more silica, the more violent the eruption

• Silica content has no effect on the violence of the eruption

What type of lava is characterized by a jagged, sharp, and blocky texture?

• Pahoehoe lava

• Aa lava

• Rhyolite lava

• Basaltic lava

Which type of igneous rocks are composed of high silica content?

• Mafic igneous rocks

• Felsic igneous rocks

• Intermediate igneous rocks

• Ultramafic igneous rocks

What type of volcano is characterized by broad, low gradient edifice and composed of basaltic lava flows?

• Strato-volcano

• Shield volcano

• Cinder cone volcano

• Composite volcano

Which type of volcano has a typical life span ranging from 200,000 to 2 million years?

• Cinder cone volcano

• Shield volcano

• Strato-volcano

• Composite volcano

What type of volcanic eruption is typically associated with a composite (strato) volcano?

• Mild eruption

• Violent eruptions/dangerous to humans/property

• Non-explosive eruption

• Effusive eruption

Which of the following is a characteristic of a cinder cone volcano?

• Tall (25,000ft) and large base

• Composed of basaltic lava flow and scoria

• 50,000 - 700,000 year life

• Violent eruptions/dangerous to humans/property

What is a lahar?

• A hot or cold mixture of water and rock fragments that flows down the slopes of a volcano

• A large volcanic crater formed by a major eruption leading to the collapse of the mouth of the volcano

• A type of volcanic rock ejected during an eruption

• A broad plateau formed when basaltic lava flows out of long fissures instead of central vents