Idea for Use in the Classroom

Why do volcanoes form where they do? Is there a connection between the location of extinct volcanoes and active volcanoes? Use the Earth’s Major Volcanoes map to explore these ideas. Prepare students by reviewing the sources of volcanism, namely, hotspots in the mantle and plate tectonics. Explain that hotspots are not stable and do not remain at the same location at all times. Additionally, students should understand how plates move over time and the effects of this movement. Have students identify the likely source of volcanism for each active volcano on the map. Then, have students compare the locations of the active volcanoes to the extinct volcanoes. Ask them to consider why the extinct volcanoes tend to be close to the active volcanoes. Given what they know about the active volcanoes, have students identify the past source of the extinct volcano.

To extend this activity, have students research and plot the locations of the other volcanoes in the Hawaiian-Emperor seamount chain. Ask students: Do you think that this chain comes from a hotspot in the mantle or plate tectonics? How would you explain the bend in the chain?


active volcano
Noun

volcano that has had a recorded eruption since the last glacial period, about 10,000 years ago.

extinct volcano
Noun

volcano that will no longer erupt.

Hawaii-Emperor Seamount Chain
Noun

underwater mountain range in the north Pacific Ocean, stretching from the U.S. state of Hawaii to southeast Japan.

Noun

middle layer of the Earth, made of mostly solid rock.

plate tectonics
Noun

movement and interaction of the Earth's plates.

volcanism
Noun

upward movement of molten material from within the Earth to the surface, where it cools and hardens.