Destructive plate boundaries occur where an oceanic plate subducts under a continental plate. As the oceanic plate descends it starts to melt from friction, forming magma. This magma can rise to the surface and form volcanoes. Examples of destructive plate boundaries include the Andes Mountains, formed by the subduction of the Nazca Plate under the South American Plate. Living in areas near destructive plate boundaries poses challenges from earthquakes and volcanic eruptions.