Outcome: The Formation of Volcanoes

Describe the processes that form volcanoes.

Volcanoes are a vibrant manifestation of plate tectonics processes. Volcanoes are common along convergent and divergent plate boundaries. Volcanoes are also found within lithospheric plates away from plate boundaries. Wherever mantle is able to melt, volcanoes may be the result.

Active volcanoes, plate tectonics, and the ring of fire. Most volcanoes are located on the borders between places, especially along the borders of the pacific pate (known as the ring of fire). However there are some, including the hawaiian hot spot and the mid atlantic ridge that are in the middle of plates. The Java trench and the Aleutian trench run along side notable chains of volcanoes and are on the border of the Eurasian plate where it meets the indo-austrian plate and the pacific plate respectively.

Figure 1. World map of active volcanoes.

See if you can give a geological explanation for the locations of all the volcanoes in figure 1. What is the Pacific Ring of Fire? Why are the Hawaiian volcanoes located away from any plate boundaries? What is the cause of the volcanoes along the mid-Atlantic ridge?

Volcanoes erupt because mantle rock melts. This is the first stage in creating a volcano. Remember from the chapter “Rocks” that mantle may melt if temperature rises, pressure lowers, or water is added. Be sure to think about how melting occurs in each of the following volcanic settings.

What You’ll Learn to Do

  • Describe various volcanic processess at plate boundaries
  • Understand the development of hotspots and their common locations

Learning Activities

The learning activities for this section include the following:

  • Reading: Volcanoes at Plate Boundaries
  • Reading: Volcanoes Hotspots
  • Reading: Volcano Formation
  • Self Check: The Formation of Volcanoes


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