volcano complex volcano A volcano with more than one feature. They form because changes of their eruptive characteristics or the location of multiple vents in an area. Stratovolcanoes may form complex volcanoes, because they may overlap another from explosive eruptions, lava flows, pyroclastic flows and by repeated eruptions, to make multiple summits and vents. Stratovolcanoes could also form a large caldera that gets filled in by multiple small cinder cones, lava domes and craters may also develop on the caldera's rim. ENVO ENVO:00000371 Wikipedia:Complex_volcano compound volcano