OVSICORI-UNA reported that during 4-11 July plumes of water vapor, aerosols, and magmatic gases rose as high as 500 m above Turrialba’s crater rim, and on most nights incandescence emanated from Cráter Oeste. The emissions sporadically contained moderate amounts of ash during 5-7 July. Minor ashfall was reported in Coronado (San José), and in San Rafael and Barva (Heredia). Parque Nacional Volcán Turrialba staff reported that ash was deposited in the region between La Silvia and La Picada farms. Events at 1325 on 10 July and 1545 on 11 July generated plumes that rose 300 and 500 m above the crater rim, respectively.

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)