Pahoehoe

Synonym: Ropy lava landscape

Pahoehoe is a type of volcanic landscape characterised by a wavy lava flow that looks like a rope. It has the following characteristics: (1) the lava surface is wavy, bulges up or is curvy, and it is called ropy lava when the extent of the curvature is small; (2) the lava flow is generally thin (1–5 m thick); (3) pores usually develop on both the top and bottom of the lava flow, debris materials are absent, and there is occasionally a thin ‘clastic layer’ at the bottom; (4) large pores or vents can form; and (5) lava blocks are transitional features along the edges or in the flow direction. The wavy pattern of the lava looks like a rolled-up rope and often appears as small rock flows. In particular, the rope shape is more pronounced in secondary lava flows. The protruded part of the rope-like feature often points in the flow direction. Based on the shape of the ropy lava, the direction of its protrusions and the intersection relationships, the lava flow...