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Report on Turrialba (Costa Rica) — 28 September-4 October 2016


Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 28 September-4 October 2016
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2016. Report on Turrialba (Costa Rica) (Sennert, S, ed.). Weekly Volcanic Activity Report, 28 September-4 October 2016. Smithsonian Institution and US Geological Survey.

Weekly Report (28 September-4 October 2016)


Costa Rica

10.025°N, 83.767°W; summit elev. 3340 m

All times are local (unless otherwise noted)

OVSICORI-UNA reported that continuous ash emissions of varying intensity rose from Turrialba during 26-29 September. On the morning of 30 September emissions reduced and rose passively no more than 100 m above the crater. Tremor was constant but had a low amplitude. Later that day intermittent gas, steam, and ash plumes rose as high as 500 m and drifted W and SW. Intermittent eruptions during 2-3 October produced ash plumes that rose no higher than 1 km and drifted S, SSW, SW, and NNE. Ashfall and a sulfur odor were reported in multiple areas downwind. Activity increased at 0823 on 3 October, with almost continuous emissions rising at most 1 km, and continued steadily through 4 October.

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 IrazĂș 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)