Active lava channel on surface of `a`a flow, Kilauea Volcano, 

1. Photograph by J. Babb on 16 August 1990

Inactive lava channel, Kilauea Volcano, Hawai`i

2. Photograph by J. Dixon

Lava channel

Channels are narrow, curved or straight open pathways through which lava moves on the surface of a volcano. The volume of lava moving down a channel fluctuates so that the channel may be full or overflowing at times and nearly empty at other times. During overflow, some of the lava congeals and cools along the banks to form natural levees that may eventually enable the lava channel to build a few meters above the surrounding ground.

Image 1: Lava moves down a channel on the surface of an `a`a flow on Kilauea Volcano, Hawai`i. Note the smooth-textured surface on the sides of the channel that mark a previous peak flow level.

Image 2: The walls of this inactive lava channel record the different heights of the lava surface during the flow's waning stages (note small terraces on right and top left).