Why do volcanoes often sit in arcs near the edges of oceans?
Quick Answer
Many ocean-edge volcanic arcs form above subduction zones, where one tectonic plate sinks beneath another. Water released from the descending plate helps melt mantle rock and create magma.
The Full Story
Volcanic arcs often occur where an oceanic plate dives beneath another plate at a subduction zone. As the sinking slab descends, it carries water-rich minerals into the mantle. That water lowers the melting point of surrounding rock, producing magma that rises to the surface in a chain of volcanoes. Famous examples include the Andes in South America and the island arc of Japan. This is why many of the world’s most active volcanoes line the Pacific “Ring of Fire.”
Key Facts
YouTube Angle
Suggested video title for this topic:
"Why do volcano chains trace the edges of the Pacific Ocean?"
Was this answer helpful?
Tap a reaction — it helps us pick what to cover next.