Report on Rincon de la Vieja (Costa Rica) — 14 June-20 June 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 June-20 June 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Rincon de la Vieja (Costa Rica). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 14 June-20 June 2017. 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 on 15 June a diffuse plume of mainly water vapor rose 50 m above Rincón de la Vieja's crater rim. A small hydrothermal explosion from the crater with the highly acidic lake was detected around noon on 18 June. In a report posted the next day OVSICORI-UNA noted that seismicity was characterized by low-frequency events, volcano-tectonic events, and tremor with intensifying amplitude; the seismic patterns were similar to those that preceded the phreatomagmatic events on 23 May and 11 June, though the recent seismicity was not as energetic.
Geologic Background. 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 that was 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 1916-m-high 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 3500 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.