Costa Rica News – Is this signs of things to come? Magma!!!!
They have verified by examining ash and gas emanations that it was the rise of magma that caused the activity.
The Volcanological and Seismological Observatory of Costa Rica and the National Seismological Network issued reports of the findings, including notes on the deformation of the structure.
It seems that the amount of fragmented fresh lava has been increasing over time. In 2010, the percentage was just 2% of the ash. It rose to 9% in 2013 and now it is up to 20%. The remaining ash corresponds to pulverized rock.
There is a progressive rise of the magmatic reservoir 04.06 km under the volcano.
As the magma moves it causes pressure on the hydrothermal system leading to breaks and steam output.