Global Volcanism Program | Image GVP-03313
Pressure ridges, formed when moving, still-fluid magma buckled the solidified surfaces of pahoehoe lava flows, are one of the many lava flow features easily observed at Craters of the Moon National Monument in Idaho.
Photo by Lee Siebert, 1994 (Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.
Craters of the Moon