Volcanoes and Volcanism - The Changing Earth: Exploring Geology and Evolution - page 106

OUTLINE
Introduction
Volcanism and Volcanoes
What Are the Types of Volcanoes?
Other Volcanic Landforms
GEO-INSIGHT: Types of Volcanoes
Distribution of Volcanoes
North America's Active Volcanoes
Plate Tectonics, Volcanoes, and Plutons
GEO-FOCUS: The Bronze Age Eruption of Santorini
Volcanic Hazards, Volcano Monitoring, and Forecasting Eruptions
Geo-Recap

OBJECTIVES
At the end of this chapter, you will have learned that
In addition to lava fl ows, erupting volcanoes eject pyroclastic
materials, especially ash, and gases.
Geologists identify the basic types of volcanoes by their
eruptive style, composition, and shape.
Although all volcanoes are unique, most are identifi ed as shield
volcanoes, cinder cones, or composite volcanoes.
Volcanoes characterized as lava domes tend to erupt
explosively and thus are dangerous.
Active volcanoes in the United States are found in Hawaii,
Alaska, and the Cascade Range of the Pacifi c Northwest.
Eruptions in Hawaii and Alaska are commonplace, but only
two eruptions have occurred in the continental United States
during the 1900s and one in 2004. Canada has had no
eruptions during historic time.
Some eruptions yield vast sheets of lava or pyroclastic materials
rather than volcanoes.

■

■

■

■

■

■

■

Lava fl owing into the sea forms new land and Hawaii becomes larger.

107

107