Global Volcanism Program | Image GVP-04247
Geologists stand in front of a steep lava flow margin in the Río Tabacón. Lava emission began on 19 September 1968, and in October the flow was advancing at rates of 10-30 m/day. By the time of this photo in November 1968 it had reached about 2.5 km from its source on the western flank. This area has now been buried by younger flows.
Photo by William Melson, 1968 (Smithsonian Institution).