Global Volcanism Program | Image GVP-01646
The toe of a blocky lava flow above members of a volcanological field team at Ulawun volcano in February 1970. The lava flow traveled 5 km from the summit, covering a broad area on the upper SW flank before being restricted to a narrow valley on the lower W flank. At its distal end, the flow front was 50 m wide and 8 m high and advanced slowly at a rate of 10 m/hour.
Photo by Robert Citron, 1970 (Smithsonian Institution; courtesy of William Melson)