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Report on Rincon de la Vieja (Costa Rica) — 22 April-28 April 2020


Rincon de la Vieja

Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 22 April-28 April 2020
Managing Editor: Sally Sennert.

Please cite this report as:

Global Volcanism Program, 2020. Report on Rincon de la Vieja (Costa Rica) (Sennert, S, ed.). Weekly Volcanic Activity Report, 22 April-28 April 2020. Smithsonian Institution and US Geological Survey.

Weekly Report (22 April-28 April 2020)

Rincon de la Vieja

Costa Rica

10.8314°N, 85.3364°W; summit elev. 1729 m

All times are local (unless otherwise noted)


OVSICORI-UNA reported periodic phreatic explosions at Rincón de la Vieja during 22-28 April. At 0535 on 22 April a phreatic event was recorded by the seismic network; weather conditions prevented good visual observations, though a steam plume was seen rising 1.5 km above the crater rim. There were five events recorded by the seismic network during the morning of 24 April, with most producing steam-and-gas plumes that rose 300-500 m above the crater rim. The largest event, recorded at 1020, ejected water and solid material 300 m above the crater rim and a steam plume that rose 1 km. An event at 1547 on 26 April ejected sediment 200 m above the rim and plumes 300 m above the rim. A plume with no ash rose 1 km at 1720 on 27 April.

Geological Summary. Rincón de la Vieja is a volcanic complex in the Guanacaste Range of NW Costa Rica. Sometimes referred to as the Rincon de la Vieja-Santa María Volcanic Complex, it consists of a slightly arcuate 20-km-long ridge of 12 craters and pyroclastic cones 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. The Santa María cone, the highest peak of the complex, is located on the E side of the ridge and has a lake within the 400-m-diameter 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 reported eruptions possibly dating back to the 16th century, have been from the active crater, near the center of the complex, with an acidic 300-m-diameter lake.

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