OVSICORI-UNA reported that at 1240 on 5 February passive gas-and-ash emissions rose from Turrialba; foggy conditions prevented estimates of ash-cloud height and drift direction, although the plume likely drifted SW. Residents of La Silvia, 2 km NW, reported a sulfur odor and ashfall. For a period of 15 minutes, starting at 1350 on 6 February, passive gas-and-ash emissions rose about 500 m above West Crater and drifted NW. According to the Washington VAAC the webcam recorded gray emissions on 8 February.

Geological Summary. Turrialba, the easternmost of Costa Rica's Holocene volcanoes, is a large vegetated basaltic-to-dacitic stratovolcano located across a broad saddle NE of Irazú volcano overlooking the city of Cartago. The massive edifice covers an area of 500 km2. Three well-defined craters occur at the upper SW end of a broad 800 x 2200 m summit depression that is breached to the NE. Most activity originated from the summit vent complex, but two pyroclastic cones are located on the SW flank. Five major explosive eruptions have occurred during the past 3500 years. A series of explosive eruptions during the 19th century were sometimes accompanied by pyroclastic flows. Fumarolic activity continues at the central and SW summit craters.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA), Washington Volcanic Ash Advisory Center (VAAC)