Chapter 7 Summary and Questions for Review

The topics covered in this chapter can be summarized as follows:

Topics Covered in Chapter 7
7.1 Plate Tectonic Settings of Volcanism The relationships between plate tectonics and volcanism, including the various mechanisms for the formation of magma and the evolution of that magma prior to the volcanic eruptions.
7.2 Magma Composition and Eruption Style A review of the range of magma compositions at different types of volcanoes, how magma evolves within magma chambers, and the relationships between magma composition, viscosity, and gas content and eruption style.
7.3 Types of Volcanism A summary of the various types of volcanoes that form in different volcanic settings, their typical sizes and shapes and their eruption characteristics. Examples of each type are also described.
7.4 Volcanic Hazards A review of the common types of hazards associated with different types of volcanic eruptions, and the direct and indirect effects that these can have on human populations, infrastructure and the environment.
7.5 Monitoring Volcanoes and Predicting Eruptions The signs that we can expect to observe when a volcanic eruption is imminent, and the tools and techniques that can be used to monitor volcanic regions so that we can predict eruptions and minimize casualties.
7.6 Effects of Volcanic Eruptions on Humans and Earth Systems Humans use volcanic landforms and volcanic products in many different ways, including farming, recreation, energy and minerals, but volcanic eruptions also create many different types of hazards that can lead to injury or death of thousands. Volcanic eruptions also contribute to Earth systems in many ways, but primarily in cycling solids, volatiles and energy from the mantle and crust onto land, into water, and into the atmosphere.

Review Questions for Chapter 7

Answers for the review questions can be found in Appendix 1

  1. What are the three main tectonic settings for volcanism on Earth?
  2. What is the primary mechanism for partial melting at a convergent plate boundary?
  3. Why are the viscosity and gas content of a magma important in determining the type of volcanic rocks that will be formed when an eruption takes place?
  4. Why do the gases in a magma not form gas bubbles when it is deep within the crust?
  5. Describe the main mechanism through which a magma chamber could become zoned.
  6. What two different types of rock textures are typically associated with a composite volcano?
  7. What is a lahar, and why are they commonly associated with eruptions of composite volcanoes?
  8. Under what other circumstances might a lahar form?
  9. Explain why composite volcanoes tend to have steeper slopes than shield volcanoes.
  10. What is a pyroclastic density current, and why are they dangerous?
  11. Why is there typically weak seismic activity (small earthquakes) associated with the early stages of a volcanic eruption?
  12. How can GPS technology be used to help monitor a volcano that has the potential to erupt?
  13. Why are many volcanic regions particularly suitable for agriculture?
  14. What was the likely cause of most of the deaths at the 2002 eruption of Mt. Nyiragongo?
  15. Volcanoes bring materials to surface from depth in the mantle. Explain why that might be an important contribution to the Earth system.




Environmental Geology Copyright © by Steve Earle. All Rights Reserved.

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