Report on Rincon de la Vieja (Costa Rica) — 29 August-4 September 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
29 August-4 September 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Rincon de la Vieja (Costa Rica). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 August-4 September 2018. 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 two distinct, two-minute-long eruptions at Rincón de la Vieja beginning at 0434 and 1305 on 31 August. Weather conditions prevented webcam views and estimates of plume heights.
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.