As of this writing Kilauea enters its 17 th year of near continuous eruption the longest sustained eruption recorded historically. Pu u' O o s lava fountains attained heights as high as 1500 ft. Lava fountains are propelled upward by intense expanding gases in the magma. Three of the most common volcanic features people see are pahoehoe lava, a a lava, and cinder cones. A lobe of pahoehoe slowly oozes forward.
Pahoehoe is the smooth unbroken lava that looks like the top of a brownie pan.
Pahoehoe is generally hotter than a a, and contains more dissolved gases which results in a more fluid flow. An advancing flow of a a lava crushes a deserted pick-up truck. A a is the jagged, broken lava that looks like it was bulldozed. It is more viscous than pahoehoe. Similar to a river freezing the cooling chunks on the surface are rafted along with the molten mass.