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Report on Turrialba (Costa Rica) — 29 April-5 May 2015


Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
29 April-5 May 2015
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2015. Report on Turrialba (Costa Rica). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 April-5 May 2015. Smithsonian Institution and US Geological Survey.

Weekly Report (29 April-5 May 2015)


Costa Rica

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

All times are local (unless otherwise noted)

OVSICORI-UNA reported that a 4-minute-long ash emission from Turrialba occurred at 0836 on 1 May. The ash plume rose about 500 m above the crater and drifted SW. Ash emissions that began at 1524 on 4 May lasted 23 minutes, and produced an ash plume that rose 2.5 km and drifted SW. The eruption ejected ballistics 1 km from the crater. Most of the ashfall occurred around the crater. Reports of minor ashfall and sulfur odors came from San José (Moravia, Coronado, Mata de Plátano, La Uruca, Guadalupe, Tibás, Calle Blancos, San Pedro Montes de Oca, Sabanilla Montes de Oca, Pavas, Zapote, Escazú, S of San José, Paso Ancho, Curridabat, Santa Ana), and a few localities in the eastern region of Heredia. On 5 May intermittent emissions of gas and ash rose 500 m; inclement weather prevented satellite observations.

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)