Global Volcanism Program | Image GVP-06261
People at the Arenal Volcano Observatory watch a S-flank pyroclastic flow on 23 January 1991. Pyroclastic flows occasionally descended the flanks throughout the long-lived eruption that began in 1968.
Photo by McDiarmid, 1991 (courtesy of William Melson, Smithsonian Institution).
This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.
Galleries: Volcano Monitoring