Kaumana Lava Tube: Photograph by Will Tenney

Kaumana Lava Tube

When lava flows slowly down the gentle slopes of Hawai‘i’s shield volcanoes the surface can sometimes cool and solidify while hot liquid lava still flows beneath the surface. At times this flowing subterranean lava forms “lava tubes.” After the flow has ended and all the rock has cooled, some of the tubes remain. Scattered around Hawai‘i are many examples of lava tubes, caves which can run long distances underground. This tube at Kaumana on the Saddle Road just outside of Hilo collapsed leaving an open section (a “skylight”) which is now an access point for visitors. The tube was formed during an 1881 lava flow from Mauna Loa, the more active of the two giant volcanoes on Hawai‘i.