Hawaiian eruptions may occur at a central vent or along fissures that act as linear vents. in the event of an eruption along a fissure, the fluid lava feeds extensive streams which flow downslope. when the eruption is at a central vent, the lava may be spewed several hundred feet into the air which may then build up the existing cone, feed lava flows, or form lakes of lava within the crater. very little ash is ejected.