Most volcanoes form at which plate boundary type according to this material?

• A. Divergent boundaries
• B. Convergent boundaries with subduction
• C. Transform boundaries
• D. Hotspot centers within plates

Answer: (B)

Most volcanoes form at convergent boundaries with subduction. When one plate sinks beneath another, water and other volatiles carried by the subducting slab lower the melting point of the overlying mantle, producing magma. This magma is often silica-rich and viscous, which traps gases and leads to explosive eruptions. The magma then rises to the surface, forming volcanic arcs along the edge of the overriding plate. This setup is responsible for the majority of Earth's volcanoes, especially around the Pacific Ring of Fire. While volcanism also occurs at divergent boundaries (mid-ocean ridges), hotspots within plates, and other settings, subduction zones at convergent boundaries account for most volcanoes.