A point source of the Earth's surface through which lavas, pyroclastics, and gas are erupted. The eruptive products have their thickest accumulation around the point source and build up a low-angle shield or higher-angle cone topography constituting the volcanic pile. Later eruptions may occur from fissures within the volcanic pile, which radiate and are fed from the point source. Continuous release of gas (explosive or quiet) from the point source ensures the existence of an open vent at the top of the volcanic pile. This vent can often be enlarged by the peripheral collapse of its walls. See also volcano.
Subjects: Earth Sciences and Geography.