At 0946 on 29 July an eruptive event generated a plume that rose 200-300 m above Turrialba’s crater rim. Several ash eruptions (10) were recorded for a period starting at 2010 on 30 July and ending at 0940 on 31 July. Each event lasted less than 10 minutes and plumes rose no higher than 200 m. An incandescent area was visible on the SW wall of the crater. At 0746 on 1 August a plume rose 500 m and at 0545 on 4 August a plume rose 300 m.

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)