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