Global Volcanism Program | Image GVP-04255
The margins of a lava flow descending the WNW flank of Arenal rise above a monument to victims of a powerful explosive eruption in July 1968. Lava flow effusion began on 19 September 1968 and by the time of this December 1968 photo had reached about 2 km from the vent on the lower west flank.
Photo by Dick Berg, 1968 (courtesy of William Melson, Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.