Study Notes for EMES101 Lesson 6: Volcanoes

Flashcards created from lecture notes on volcanoes to enhance understanding before the exam.

What is the purpose of the study guide in Lesson 6 about volcanoes?

To evaluate knowledge and target concepts for better study.

How should students prioritize questions they can't answer in the study guide?

Focus on them first before partially answerable questions.

What are the two criteria for classifying igneous rocks?

Composition and texture.

What texture does volcanic glass have compared to other igneous rocks?

Glassy texture; forms faster than phaneritic and aphanitic.

What is a porphyry classified as and why?

It is an igneous rock because it has a porphyritic texture.

How does color indicate the silica content of igneous rocks?

Generally, lighter colors indicate higher silica content.

What two main factors determine explosivity in volcanic eruptions?

Composition and gas content.

Give an example of a viscous fluid and a non-viscous fluid.

Viscous: honey; Non-viscous: water.

What is the significance of temperature and composition in a volcano’s explosivity?

Higher temperature and lower composition generally lead to less explosivity.

What mechanisms lead to the formation of pyroclastic debris?

Eruptive processes that blast solid materials into the air.

What are the three most abundant volcanic gases?

Water vapor, carbon dioxide, and sulfur dioxide.

How does a lava dome relate to volcanic cones?

They are generally associated with stratovolcanoes due to their viscosity.

What are the physical differences between the three types of volcanic cones?

Cinder cones are steep, shield volcanoes are broad and gently sloping, stratovolcanoes are steep and layered.

What defines a caldera?

A large depression formed by the collapse of an overlying rock after a volcanic eruption.

What is the role of viscosity, temperature, and silica during volcanic eruptions?

They affect the type of volcanic products produced (e.g., lavas vs. pyroclastic material).

How are lahars formed and why are they unpredictable?

They are volcanic mudflows that occur post-eruption and are difficult to forecast.

What makes Mt. Rainier a dangerous volcano?

Its potential for deadly lahars and its proximity to populated areas.

What are pyroclastic flows and why are they hazardous?

Fast-moving currents of hot gas and volcanic matter that can devastate areas near volcanoes.

What is a volcanic ash hazard?

It can cause respiratory issues and disrupt air travel when ejected into the atmosphere.

How do stratovolcanoes differ from other volcano types?

They are formed primarily from alternating layers of lava flows and pyroclastic debris.