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Report on Rincon de la Vieja (Costa Rica) — December 1994


Rincon de la Vieja

Bulletin of the Global Volcanism Network, vol. 19, no. 12 (December 1994)
Managing Editor: Richard Wunderman.

Rincon de la Vieja (Costa Rica) Minor seismicity

Please cite this report as:

Global Volcanism Program, 1994. Report on Rincon de la Vieja (Costa Rica) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 19:12. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199412-345020



Rincon de la Vieja

Costa Rica

10.8314°N, 85.3364°W; summit elev. 1729 m

All times are local (unless otherwise noted)


During December 1994, Rincón de la Vieja was seismically active. The local station (5 km SW of the active crater) registered three small-amplitude events on 19 December and, at 2121, a fourth of Richter magnitude 3.0. The last event had a focal depth of 23 km and an epicenter 4.5 km NE of the active crater. One event took place each day on 23, 24, and 25 December; these events each had an S -P delay in the range of 1.9 to 2.5 seconds.

Geological Summary. Rincón de la Vieja is a volcanic complex in the Guanacaste Range of NW Costa Rica. Sometimes referred to as the Rincon de la Vieja-Santa María Volcanic Complex, it consists of a slightly arcuate 20-km-long ridge of 12 craters and pyroclastic cones constructed within the 15-km-wide early Pleistocene Guachipelín caldera, whose rim is exposed on the south side. Sometimes known as the "Colossus of Guanacaste," it has an estimated volume of 130 km3 and contains at least nine major eruptive centers. The Santa María cone, the highest peak of the complex, is located on the E side of the ridge and has a lake within the 400-m-diameter crater. A Plinian eruption producing the 0.25 km3 Río Blanca tephra about 3,500 years ago was the last major magmatic eruption. All subsequent eruptions, including numerous reported eruptions possibly dating back to the 16th century, have been from the active crater, near the center of the complex, with an acidic 300-m-diameter lake.

Information Contacts: OVSICORI.