A linear fracture on the Earth’s surface through which lavas, pyroclastics, and gas are erupted and effused. The eruptive products accumulate most thickly along the linear fracture and build up an elongate, low-angle shield or higher-angle cone topography, constituting the volcanic pile. In addition to eruptions from the main fissure, material can be erupted from secondary fissures developed locally within the growing volcanic pile and radiating from the trend of the main fissure. See also central vent volcano; volcano.