OVSICORI-UNA reported that at 1259 on 6 February a small phreatic eruption at Turrialba’s Cráter Oeste produced an ash plume that rose 100 m above the crater rim. A thermal anomaly from the floor of Cráter Oeste was identified in satellite images on 4 February. The anomaly was last seen in the same location on 25 January, and twice in 2021, during clear weather conditions; the location of the anomaly was the same in those images since March 2021, and likely represented a hot crack venting on the crater floor. Two incandescent points in the crater were visible in overnight webcam images during 7-8 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.

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)