| a curving chain of active volcanoes formed above a subduction zone and adjacent to a convergent plate boundary. |
| volcanic arc n. A usually arc-shaped chain of volcanoes located on the margin of the overriding plate at a convergent plate boundary. |
volcanic arc  (vŏl-kān'ĭk, vôl-) Pronunciation Key
A curved chain of volcanoes in the overriding tectonic plate of a subduction zone. Volcanic arcs form as the result of rising magma formed by the melting of the downgoing plate. They are curved because of the curvature of the Earth. The Andes mountains form a volcanic arc. See also island arc. |