VHP Photo Glossary: Spatter cone
Spatter cones are low, steep-sided hills or mounds of welded lava fragments that form along a linear fissure or around a central vent. As lava fragments erupt into the air, they often do not have time to cool completely before hitting the ground. Consequently, the fragments "spatter" as they land and bond to the underlying lava fragments, which are still hot and sometimes oozing down the side of the cone.
Photo: Lava pours from the base of spatter cones built atop a fissure on the southwest flank of Pu`u `O`o (note slope in lower left), Kilauea Volcano, Hawai`i.