Report on Rincon de la Vieja (Costa Rica) — 23 June-29 June 2021
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 23 June-29 June 2021
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2021. Report on Rincon de la Vieja (Costa Rica) (Sennert, S, ed.). Weekly Volcanic Activity Report, 23 June-29 June 2021. Smithsonian Institution and US Geological Survey.
Rincon de la Vieja
10.83°N, 85.324°W; summit elev. 1916 m
All times are local (unless otherwise noted)
OVSICORI-UNA reported that at 0542 on 28 June an eruption at Rincón de la Vieja produced a steam-and-ash plume that rose 2 km above the crater rim and ejected material onto the flanks. Residents in Gavilan de Dos Ríos (7 km N and NNW) and Bromelias (6 km NNE) reported volcanic gas odors and ashfall. Lahars descended multiple drainages on the N flank.
Geological Summary. 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.