Santiago

The ropy texture of pahoehoe lava flows is produced when the thin solidified surface of the flow is pushed by the advancing, still-molten interior. This pleated pahoehoe lobe, on a lava flow at Santiago shield volcano in the Galapagos Islands, advanced slowly from the bottom right to the upper left. Pahoehoe lavas are the least viscous of common lava types, and thus form spectacular surface structures.