Volcanoes in Costa Rica have certainly made headlines this year, the National University’s Volcanology and Seismology Research Institute (OVSICORI) offered its annual report on the country’s volcanic activity.

“Turrialba Volcano has maintained an open system activity, generating passive emissions of ash as a result of the slow but almost constant raise of a small volume of magma. Out of the 336 days of the year (through the day of the report), the volcano had emissions of ash in 194 days, which represents over 58% of the days (…) There was an increase in the activity during the months of February and March and then in May and October. Since the end of October, there has been a decrease in the magmatic activity but not in the emissions of ash. It is considered that the hydrothermal system is forming again generating explosive interactions magma-water and fragmentation of magma in the column giving origin to the emissions of ash. (…) It is recommended to consider the volcano as dangerous for as long as it maintains active”. (Classified with level of activity 3 – volcano in eruption)

“During 2018, the Poas volcano maintained a low activity, dominated by hydrothermal process and degasification. There were no reports of explosive eruptions, but there were several periods of sustained activity. The flow of gas decreased considerably in comparison to 2017, and the hydrothermal system formed again, which was evident in January with the reappearance of the lake, which disappeared again during the dry season (March-May) and once again it appeared generating variability in the monitored signals. The color of the lake changed from grey to green at the end of the year, and through mid-December the eruptive activity increased, generating hydrothermal eruptions with columns of water vapor and the almost disappearance of the lake”. (level of activity 2 – active volcano)

“The Rincón de la Vieja Volcano maintained during 2018 an intense phreatomagmatic activity with frequent phreatic and phreatomagmatic eruptions of lower amplitude than in 2017”. (level of activity 3-volcano in eruption)

When it comes to the Irazú volcano, the level of activity is classified as 1 (active), however the associated volcanic activity was very low. No magmatic activity has been detected in this Volcano.

Arenal, Tenorio, Platanar and Barva volcanoes remain dormant.