Report on Turrialba (Costa Rica) — June 1996
Bulletin of the Global Volcanism Network, vol. 21, no. 6 (June 1996)
Managing Editor: Richard Wunderman.
Turrialba (Costa Rica) Microseismicity escalates from 0 (background) to 246 events/month
Please cite this report as:
Global Volcanism Program, 1996. Report on Turrialba (Costa Rica). In: Wunderman, R. (ed.), Bulletin of the Global Volcanism Network, 21:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199606-345070.
10.025°N, 83.767°W; summit elev. 3340 m
All times are local (unless otherwise noted)
After 23 May Turrialba's seismic station (VTU, located 0.5 km E of the active crater) registered a sudden increase in microseismicity. During the first four months of 1996 nearly no events were registered. In late May there were over 50 events; in June, 246 events. The dominant frequency of these events varied between 2.5 and 4.0 Hz.
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.
Information Contacts: Erick Fernández, Elicer Duarte, Vilma Barboza, Rodolfo Van der Laat, and Enrique Hernandez, Observatorio Vulcanológico y Sismológico de Costa Rica, Universidad Nacional (OVSICORI-UNA), Apartado 86-3000, Heredia, Costa Rica.