Report on Turrialba (Costa Rica) — 18 January-24 January 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 18 January-24 January 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Turrialba (Costa Rica). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 January-24 January 2012. Smithsonian Institution and US Geological Survey.
10.025°N, 83.767°W; summit elev. 3340 m
All times are local (unless otherwise noted)
OVSICORI-UNA reported that on 12 January a new vent opened on the SE flank of the W crater of Turrialba and ash emissions drifted NNE; ashfall was reported in Tres Ríos (27 km SW). During the evening of 18 January scientists observed gas emissions and ejection of tephra from the vent. They also observed reddish flames from combusting gas, estimated to be about 700 degrees Celsius. Residents reported a dark ash cloud and ashfall in La Central (4 km SW). An OVSICORI-UNA pilot observed an ash plume that rose to altitudes of 4.3-6.1 km (14,000-20,000 ft) a.s.l. on 18 January.
Geologic Background. 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.