The experts believe that the volcanoes are not synchronized.
Nowadays, there are only 5 geologically active volcanoes in the country.
Many phreatic eruptions have been seen in the Poas Volcano Lagoon lately
Three volcanoes attract the Costa Ricans and volcanologists’ attention because of their continuous volcanic activity.
In 2016, the Poas’ volcano lagoon had three violent phreatic eruptions (water and gas) Watch this video of a phreatic eruption in Poas Volcano:
Turrialba Volcano has kept the local authorities on tenterhooks since 2014 due to the intermittent eruptions of ashes and gasses throughout the last year. This type of eruptions often comes before the expulsion of lava and volcanic material. Besides that, the blasts coming from this crater caused the preventive closure of many pathways and roads, the evacuation of the nearest communities, and the suspension of flights for several days in 2016.
Rincon de la Vieja is another active volcano. During the last year, specifically in March, an ejection of ashes set off the alarms in the surrounding areas. The volcanologists have noticed a change in its volcanic activity since 2015. They believe that the massif may blast soon again according to the seismic data recorded by the Costa Rican Vulcanological and Seismological Observatory. The experts are still waiting for the expulsion of sediments from its hot lake.
Mauricio Mora, one of the volcanologists working for the National Seismic Network, explained that the volcanic activity periods of the three volcanoes are not interconnected; he added that each volcano actually acts independently, although Poás and Turrialba usually erupt simultaneously.
“Although Turrialba and Poas Volcano seem to come into activity at the same time, they are actually totally independent” – Mora said.
Poas is considered a volcano with a lot of phreatic activity, typical of a hydrothermal system. It means that it irregularly blasts and falls into a sudden dormant state.
But Turrialba is different because its eruptions are more catastrophic. It is an explosive volcano with occasional but apocalyptical explosions combined with short periods of calm.
Rincon de la Vieja is still timidly active due to the rupture of underground rocks and movement of fluids.
“It would be normal to see the Turrialba volcano blast again and again” – Mora explained.
Although they are the most genealogically active craters so far, there are other massifs such as the Arenal and Irazu, which are currently in action, but they still belong to the group of the 5 most current dangerous volcanoes of Costa Rica.