An arching fountain of Pahoehoe, approximately 10 m high, issuing from a spatter cone of Pu‘u Kahaualea, Hawaii. Lava, when first exuded from a volcanic vent, is a liquid at very high temperature: typically from 700°C to 1200°C. Although, the viscosity of lava is 100,000 times that of water, the viscous rock can flow many miles before eventually cooling and solidifying. Photo credit: J.D. Griggs, USGS |