Report on Rincon de la Vieja (Costa Rica) — October 1992
Bulletin of the Global Volcanism Network, vol. 17, no. 10 (October 1992)
Managing Editor: Lindsay McClelland.
Rincon de la Vieja (Costa Rica) Degassing and minor seismicity
Please cite this report as:
Global Volcanism Program, 1992. Report on Rincon de la Vieja (Costa Rica) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 17:10. Smithsonian Institution.
Rincon de la Vieja
10.83°N, 85.324°W; summit elev. 1916 m
All times are local (unless otherwise noted)
Degassing continued from the active crater. Seismic stations at the Proyecto Geotérmico de Miravalles (8-10 km from the active crater) continued to register 2-3 low-frequency volcanic events/day of <100 seconds duration. Vigorous seismicity had continued into early September, after seismic signals interpreted as probably associated with small to moderate eruptions from the lake were recorded in August.
Geologic Background. Rincón de la Vieja, the largest volcano in NW Costa Rica, is a remote volcanic complex in the Guanacaste Range. The volcano consists of an elongated, arcuate NW-SE-trending ridge 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. Activity has migrated to the SE, where the youngest-looking craters are located. The twin cone of Santa María volcano, the highest peak of the complex, is located at the eastern end of a smaller, 5-km-wide caldera and has a 500-m-wide 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 historical eruptions possibly dating back to the 16th century, have been from the prominent active crater containing a 500-m-wide acid lake located ENE of Von Seebach crater.
Information Contacts: G. Soto and R. Barquero, ICE; E. Fernández, J. Barquero, and V. Barboza, OVSICORI.