QCOSTARICA – Several residents of La Pastora, La Central and Monte Calas, in the vicinity of the Turrialba volcano, heard a loud rumbling early Sunday morning and shortly after they noticed ashfall in a range of two to three kilometers to the southwest of the crater.
According to Javier Pacheco, a researcher at the Observatorio Vulcanológico y Sismológico de Costa Rica (Ovsicori) – Costa Rica Volcanological and Seismological Observatory, the rains of the last days generated that hydrothermal eruption at 12:18 am Sunday, which raised a column of ash and gases of approximately 300 meters.
“It was a fairly strong explosion because the sound was heard by residents from nearby areas. The amount of ash was small and it did not travel much distance,” he said.
According to the scientist, this is the first eruption of this year in that volcano and others are not ruled out.
The bottom of the crater still has rocks above 500 degrees Celsius, which react when they come into contact with water.
As the hydrothermal system of the colossus was saturated by heavy rainfall and the water reached the hot rock, it immediately suddenly evaporated and produced that eruption.
The energy that activates these explosions comes from the magma that rose in the eruptive cycle that occurred between 2010 and 2018.
“All volcanoes are water reserves, they have very large aquifers. In Turrialba, when the rise of magma ceases, the aquifer recovers. As the water enters, it generates pressure in the system and that pressure opens cracks through which the liquid passes until it reaches the hot rock,” he said.
Since last week park rangers and residents have heard rumbles, which are also registered in the nearby seismic stations, but this Sunday was much more powerful.
Boiling water, steam, mud and rock fragments were erupted and thrown up to several kilometers.
It is estimated that the hot body of that volcano is less than 500 meters deep.
Pacheco said that Sunday’s boom was so strong that it was even recorded at an infrasound station that Ovsicori has in Alajuela, on the slopes of Poás.
“With the eruption a sound wave is produced, which travels at 340 meters per second and that is what people hear,” he said.
Tourist access to the Turrialba volcano viewpoint is still open, as it is at a safe distance from the crater. In addition, on the way there are shelters to protect yourself against any eventuality.
Monitoring the Ovsicori allows park rangers to be notified by radio in case any danger is noticed.
At the moment, these eruptions are part of the volcano’s process towards its state of rest and it is not about any reactivation.
The activity could continue, since the rainy season is just beginning and has the reinforcement generated by tropical waves.
Risk for sly visitors
Pacheco affirmed that the ash and gases, mainly carbon dioxide (CO2), come out at very high temperatures and those who arrive illegally on the edge of the crater are exposed to serious consequences.
“People who ascend illegally do not know what is happening and these eruptions do not give a warning. They happen from one moment to the next and people put their lives at risk, since CO2 is very harmful magmatic gas,” he explained.
CO2 is heavier than air. A person without equipment does not notice its presence, because that chemical has no color or odor. When there are outputs of large quantities, CO2 displaces oxygen for a time, as it is heavier than the latter, so that exposed people suddenly find themselves in environments without oxygen, which endangers their health and life.
Pacheco affirmed that it will take several years for the Turrialba to cool down, so that during the rainy seasons, this type of eruption will be repeated.
