Earth Science

Geological Activity from Plate Tectonics Processes

Volcanoes at Plate Boundaries

Study Tip
Knowing how volcanoes are formed, you can predict where to find volcanoes.

Convergent Plate Boundaries

  • Between the two converging plates, if one or more is oceanic, it will sink into the mantle. As a plate sinks into the mantle, it will heat up, causing the mantle to melt. This creates volcanic arcs.
  • Convergent plate volcanoes are often found along the Pacific Ocean basin.
Study Tip
Knowing how volcanoes are formed, you can predict where to find volcanoes.
Study Tip
The same way a person may cast a shadow over another person when they stand under the sun, planets or celestial bodies that have aligned themselves cast shadows over one another as well.

Divergent Plate Boundaries

  • Between two diverging plates, there will be lower pressure. Lowering pressure can lower the melting temperature of mantle, and therefore it causes mantle to melt. This creates volcanic fissures—cracks.
  • Divergent plate volcanoes are often found at mid-ocean ridges, where seafloor is pulled apart to create new seafloors. They are also found when continents break apart.
Concept Check
  • How are volcanoes created at converging plate boundaries?
  • How are volcanoes created at diverging plate boundaries?
  • What are fissures?
Volcanic region along the Pacific basin
Volcanic region along the Pacific basin
Concept Check
  • How are volcanoes created at converging plate boundaries?
  • How are volcanoes created at diverging plate boundaries?
  • What are fissures?