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Geosciences LibreTexts

9.1: Introduction

  • Page ID
    5618
  • Overview

    How would you like to live on an active volcano? Surprisingly, a lot of people are living on or near active volcanoes, and many more live near volcanoes that are currently considered to be “dormant”, exhibiting a volcanically-quiet period of time over the past 10,000 years, but with the potential to erupt in the future (Figure 9.1). Are they crazy (Figure 9.2)? Maybe some are, but not all volcanoes erupt explosively; for example, the type of volcano that forms the Hawaiian Islands is a type that erupts effusively, with lava running down the sides (flanks) of the volcano (Figure 9.3). Hawaiian citizens are familiar with this style of eruption, and they are also aware that their particular volcano will not erupt explosively. Explosive eruptions are more likely for the volcanoes that make up the Islands of Sumatra and Java (Indonesia); these volcanoes are very dangerous, and yet Indonesia is one of the most densely populated countries in the world. So, it would seem very important to know why some volcanoes are dangerous, and why others are not. Of the “dangerous” types that are currently dormant, will we have enough of a warning before they erupt? Is it only the eruption that we should worry about, or are there other hazards that we must be aware of? These questions will be addressed in this chapter, along with a few other questions that you might have, such as why volcanoes form in certain locations, especially in relation to plate tectonics, and the association of magma type with volcano type and eruptive style.

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    Key Terms

    • Composite volcano
    • Dike
    • Flood Basalt
    • Lahar
    • Lava Dome
    • Pyroclastic Flow
    • Shield Volcano
    • Silica Tetrahedron
    • Sill
    • Viscosity