Key Points in this Chapter

KEY POINTS IN THIS CHAPTER

• Volcanoes have existed since there has been crust on earth.

• There are four major volcanic structures – lava domes, cinder cones, composite, and shield volcanoes.

• Not all volcanoes emit basaltic lava, especially near subduction zones.

• Volcanoes range on a logarithmic explosivity scale from 0 to 8.

• Volcanic eruptions can involve one or more vents, gentle flows, explosive gases, and steam, depending on the different types.

• You can somewhat predict the presence of an impending volcanic eruption by measuring different things, such as gas emissions, ground deformation, sounds beneath the ground, and seismic activity.