View from the northeast edge of Halema`uma`u toward the northeast. A short-lived fissure eruption built this spatter rampart on April 30-May 1, 1982.
John posing inside a spatter cone.
Photo by Thom Wilch
When erupting lava is made of just enough explosive gas to prevent the formation of a lava flow, but not enough to shatter it into small pieces, the lava is formed by expanding gases into fluid hot clots, called spatter.
When the spatter falls back to Earth the clots weld themselves together and solidify forming steep-sided accumulations called spatter cones.