Pahoehoe lava is a term used by Hawaiian to describe lava flows with a smooth unbroken surface. The basalt lava flows are typically 1100 to 1200 degrees Centigrade when they flow out of a volcano vent. They often form lava tubes that carry lava far down the slopes where they empty into the ocean at the flow front. The lava tubes become lava caves after the eruption ceases.
Pahoehoe flow of lava on the Big Island
of Hawaii, Myrna Martin
The pahoehoe flow moves down the volcano forming a series of lobes and toes. The new lava breaks through the flow front as the lava moves down the mountain. As the basalt lava flows away from the vent it forms all kinds of bizarre shapes. The rocks are often described as rock sculptures.
Formation of lava tubes
Lava tubes sometimes form when pahoehoe flows down the sides of a volcano. The lava cools and hardens on the outside of the flow forming a tube. Skylights are breaks in the roof a lava tube that develops when part of the ceiling collapses.
Pahoehoe flow becomes aa lava flow
Cooling pahoehoe flows sometimes turn into aa lava flows. Aa lava flows never become pahoehoe flows. Aa flows are cooler and move at a much slower speed. People can sometimes walk in front of aa lava flow taking pictures as it moves forward.
Pyroclastic Rocks Find out how pyroclastic rocks form during volcanic eruptions.
Aa Lava Learn more about aa lava flows that occur on the Hawaiian Islands and the lava balls that often form on their surface.
Welded Tuff Find out how welded tuff is produced during violent eruptions and by supervolcanoes.
Intrusive Rocks Learn more about intrusive rocks that cool underground forming batholiths like the Sierra Nevada Mountains in California.
Clastic Rocks Find out how bits and pieces of older rocks form shale, sandstone and conglomerate rocks.
Pahoehoe Lava Find out how pahoehoe forms in the Hawaiian Islands.
Rock Cycle Learn more about igneous, sedimentary and metamorphic rocks and how they form.
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