Report on Rincon de la Vieja (Costa Rica) — January 1997
Bulletin of the Global Volcanism Network, vol. 22, no. 1 (January 1997)
Managing Editor: Richard Wunderman.
Rincon de la Vieja (Costa Rica) Sulfur-bearing steam, mass wasting, and acid rain in September
Please cite this report as:
Global Volcanism Program, 1997. Report on Rincon de la Vieja (Costa Rica) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 22:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199701-345020.
Rincon de la Vieja
10.83°N, 85.324°W; summit elev. 1916 m
All times are local (unless otherwise noted)
A visit to the crater during September 1996 revealed vegetation killed by the phreatic eruption of November 1995 (BGVN 20:10 and 20:11/12), by mass wasting in its aftermath, and by continued acidic rainfall. Although some plants were beginning to return, most suffered visible damage such as scalded leaves. The crater area continued to smell of sulfur and the loud noise of escaping steam could be heard from the crater's margin.
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, E. Duarte, V. Barboza, R. Van der Laat, E. Hernandez, M. Martinez, and R. Sáenz, Observatorio Vulcanológico y Sismológico de Costa Rica, Universidad Nacional (OVSICORI-UNA), Apartado 86-3000, Heredia, Costa Rica.