OVSICORI-UNA reported that occasional small ash emissions rose no higher than 100 m above the active crater at Turrialba each day during 23-29 June; no emissions were recorded on 27 June. A series of ash emissions were recorded at 1348, 1739, and 2303 on 28 June and at 0107, 0232, 0306, 0412, and 0818 on 28 June. At least two of those events (0107 and 0412) were accompanied by ballistics that were ejected onto the N wall of the active crater.

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)