Global Volcanism Program | Image GVP-04309
A geologist observes an ash column that rises to a height of 400 m above the summit crater of Poás volcano on April 25, 1989. By April 19, four days before this explosion, the crater lake of Poás had disappeared. In May 1989 ash plumes reached 1.5-2 km above the crater. During this eruption thermal activity produced sulfur cones, lakes of molten sulfur, and sulfur flows.
Photo by Gerardo Soto, 1989 (Instituto Costarricense de Electridad).