RSN and OVSICORI-UNA reported that a new eruptive phase at Turrialba began at 2240 on 6 March with minor ash emissions that rose 500 m above the vent rim and drifted NW. The activity intensified around midnight, with dense ash emissions and the ejection of incandescent blocks, and remained elevated almost until 0300 on 7 March. At 1740 activity again intensified; emissions with an increased volume of ash was recorded by the webcam from 1801-1820 drifting W. OVSICORI-UNA reported that events at 1515 on 8 March and 0920 on 13 March generated ash plumes that rose 300 m and drifted SW and NW, 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.

Sources: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA), Red Sismologica Nacional (RSN: UCR-ICE), Universidad de Costa Rica and Instituto Costarricense de Electricidad