Cinder Cones on Big Island of Hawaii
March 26, 2007
This primal scene was revealed early one morning (in August of 2005) on the way down from the Mauna Kea Observatories on the Big Island of Hawaii and shows a chain of cinder cones on the southern flank of Mauna Kea. In the background, Mauna Loa’s patchwork of dark, recent lava flows contrast sharply with Mauna Kea’s grassy surface in the foreground. The difference between the two volcanoes is evident along the Saddle Road that runs horizontally through the picture. There has not been enough time since Mauna Loa’s eruptions for plants to cover the ground. However, Mauna Kea hasn't erupted in over 4000 years and so is well-vegetated.
Cinder cones are small, steep, conical craters produced by side vents on a volcano. They seldom if ever develop lava flows and are made when molten bits of rock are propelled into the air by hot, volcanic gasses. As they fall and cool, they harden and build up a small a mountain of ash or “cinders” with a characteristic central depression where the particles first emerged. The debris in cinder cones often includes volcanic “bombs.” Bombs are smooth, aerodynamically-shaped rocks that were molten when shot our of the cinder cone -- they acquired flow marks that “froze” in place as they flew through the air and cooled.