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Report on Rincon de la Vieja (Costa Rica) — 30 August-5 September 2023


Rincon de la Vieja

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 30 August-5 September 2023
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2023. Report on Rincon de la Vieja (Costa Rica) (Sennert, S, ed.). Weekly Volcanic Activity Report, 30 August-5 September 2023. Smithsonian Institution and US Geological Survey.

Weekly Report (30 August-5 September 2023)

Rincon de la Vieja

Costa Rica

10.83°N, 85.324°W; summit elev. 1916 m

All times are local (unless otherwise noted)


OVSICORI-UNA reported that small phreatic events and gas-and-steam emissions continued at Rincón de la Vieja during 29 August-5 September. Three small eruptive events generated steam-and-gas plumes that rose 2-3 km above the crater rim during 28-29 August. Multiple events produced steam-and-gas plumes during 30-31 August. At 1526 on 1 September an eruptive event generated a steam-and-gas plume that rose 2 km above the crater rim and ejected material onto the flanks. Small events were detected in infrasound data during 2-3 September. At 1251 on 4 September a steam-and-gas plume that rose 1 km above the crater rim and drifted W. The Alert Level remained at Level 3, Orange, the third level on a four-level scale.

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.

Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)