Report on Rincon de la Vieja (Costa Rica) — 6 May-12 May 2020
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
6 May-12 May 2020
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2020. Report on Rincon de la Vieja (Costa Rica). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 6 May-12 May 2020. 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 periodic phreatic explosions at Rincón de la Vieja during 6-12 May. Phreatic explosions were recorded at 1624 on 6 May and 0343 on 8 May, though inclement weather conditions hindered visual confirmation. Two small emissions were noted at 1850 on 8 May and at 0020 on 9 May. An event at 1925 on 9 May generated a gas-and-steam plume that rose almost 2 km above the crater rim.
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)