Global Volcanism Program | Image GVP-00526
Climbers along a path near the summit of Sibayak volcano. The horizontal forested ridge in the center background, forming part of the southern caldera wall of Singkut, is viewed from an area of hydrothermally altered rock near the summit.
Photo by Tom Casadevall, 1987 (U.S. Geological Survey).
This image is made available as a Public Domain Work, but proper attribution is appreciated.
Keywords: hydrothermal alteration