At first glance the eruptions of the Poás and Turrialba volcanoes look different. While the plume from the colossus of Cartago looks gray, that of its alajuelense pair is rather white. Both, of course, are large.
Are these eruptions different? The press spoke with the National Emergency Commission geologist Blas Sánchez, who explained some similarities and differences between the phenomena that occur in both massifs of the Central Volcanic Range.
According to the specialist, one of the similarities is that both volcanos have groundwater occurrences. This happens when the magma of a volcano comes into contact with the soil or a surface that contains water, which evaporates quickly causing an explosion of steam, ashes and stones, among other materials.
The main difference lies in the environment: Poás has a hydrothermal system (a body of water) that traps the sediments and generates a whiter plume, because it is water vapor, whereas Turrialba shows grey plumes and higher fragmentation of the magma, increasing the presence of ash.
This is also the reason why Poás has not affected air navigation, while Turrialba has repeatedly caused the closure of Central Valley airports.
Another difference at the present time is that Poás shows a strong increase in activity, while Turrialba remains constant in its release of material.
Sánchez explained that although both volcanoes belong to the Central Volcanic Cordillera – along with Barva and Irazú- each one has completely independent activity, because there is no link between their magmatic cameras.