Report on Turrialba (Costa Rica) — 5 October-11 October 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 October-11 October 2016
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2016. Report on Turrialba (Costa Rica). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 5 October-11 October 2016. 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 during 4-5 October tremor levels at Turrialba were low. At 0600 on 6 October tremor levels rose a small amount, and coincided with an emission with minor amounts of ash that rose 1 km and drifted N and NE. Tremor levels again rose at 1054, coinciding with another ash emission. Tremor amplitude varied during 7-11 October, and almost continuous ash emissions rose no more than 500 m and drifted N, NW, W, and SW. Minor ashfall and a sulfur odor were reported in some local areas downwind.
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.