Global Volcanism Program | Image GVP-09308
An ash plume rises above vents in the summit crater of Poás volcano on May 4, 1990, near the end of an eruptive period that began in June 1987. At the time of this photo the crater lake had shrunk substantially to a small feature only several centimeters deep that fluctuated slightly with changes in rainfall recharge. Lake temperatures were >72°C (measured by infrared thermometer), and small hot springs around the lake had temperatures of 85°C. Minor explosive eruptions at Poás continued into the following month.
Photo by Jorge Barquero, 1990 (Universidad Nacional Costa Rica).