A continental arc is a curved chain of volcanoes and igneous intrusions that forms along a convergent plate boundary where one tectonic plate subducts under another tectonic plate and into the Earth's mantle beneath the first. The subduction of oceanic lithosphere under continental lithosphere causes partial melting of the mantle wedge and the formation of magma. This magma rises to the surface and erupts to form volcanoes. The volcanoes are typically aligned in a curved or arcuate shape, following the shape of the subduction zone. Continental arcs are often associated with the formation of mountain ranges and can be a source of earthquakes and tsunamis. Examples of continental arcs include the Andes Mountains in South America and the Cascade Range in North America.