Report on Rincon de la Vieja (Costa Rica) — February 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 2 (February 1993)
Managing Editor: Edward Venzke.
Rincon de la Vieja (Costa Rica) Gas plumes rise to 500 m; lake level drops
Please cite this report as:
Global Volcanism Program, 1993. Report on Rincon de la Vieja (Costa Rica). In: Venzke, E (ed.), Bulletin of the Global Volcanism Network, 18:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199302-345020.
Rincon de la Vieja
10.83°N, 85.324°W; summit elev. 1916 m
All times are local (unless otherwise noted)
Fumarolic activity continued from the E wall of the active crater, with gas plumes rising 500 m. A strong smell of sulfur near the crater caused eye and skin irritation. Gas vents in the SE and SW parts of the crater had disappeared. Small collapses had occurred along the E and NE crater walls.
The level of the crater lake has dropped 1 m since last year. The light-gray colored lake had a temperature of 35°C in February and a pH of 1.6. The number of floating sulfur patches has decreased, and only one small bubbling area remains, producing very small intermittent bubbles.
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 that was 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 1916-m-high 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 3500 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: E. Fernández and J. Barquero, OVSICORI.