Global Volcanism Program | Image GVP-04387
An ash plume from the summit crater of Galeras volcano rises above the city of Pasto on May 5, 1989. Intermittent phreatic explosions ejected ash and blocks from the El Pinta vent beginning on February 19. Periods of stronger activity took place on March 26-27 and May 4-9. The May activity produced pyroclastic surges near the crater.
Photo by Norm Banks, 1989 (U.S. Geological Survey).