2023-08-22 04:31:11
Scientists from the National University of Río Negro (UNRN) are studying the behavior of Copahue, a volcano located in the province of Neuquén that measures almost 3,000 meters. It is the most dangerous in the country since it is active – the last eruption was recorded in December 2012 – and it has two neighboring towns within a radius of eight kilometers. For this reason, through different methods, they investigate their behavior to try to predict when the next eruptions could occur.
“We have three seismic stations installed, equipment that measures gases in the crater and theses students that model the generation of volcanic alluvium called lares. The objective is to find signs with some anticipation that indicate that there will be an event”, says Alberto Caselli, director of the Laboratory of Studies and Monitoring of Active Volcanoes (LESVA) of the UNRN.
Copahue not only leads the risk ranking for Argentina because it is active, but also because it has two nearby towns and is a place of high tourist demand due to the Villa Termal de Copahue and the Caviahue ski center, which attracts visitors from all over the world. . After its last eruption, the volcano had continuous manifestations such as sporadic emission of ash, explosions inside the crater and seismic activity of variable magnitude.
When the snow disappears, the researchers will install seismoacoustic stations to receive seismic and infrasound signals, whose job is to receive air pressure from waves generated by the volcano. In addition, they will place crater thermometers that transmit information and equipment that absorbs environmental gas four times a day.
“The idea is to see how the composition of the gas released by the crater varies along with seismic activity, sound and thermometric variations. With all this data set we want to see if we obtain a precursor signal”, explains Caselli.
Ashes, water and sulfur
Although December 22, 2012 was the last major eruption, until 2022 there were periodic explosions that spewed ash and even ejected water from the crater. Basically, this process consists of increasing the temperature of the liquid until it begins to evaporate, but at a certain moment it releases a part until the temperature drops again and the water accumulates again.
As there is a glacier on the summit of the volcano and a lake in the crater, the supply of water is permanent. Even this does not allow the fumarole to be seen (that kind of cloud or dense smoke that comes out of its interior), a key sign that indicates the presence of activity in the place. What does remain, however, is a layer of sulfur found on the surface of the lake.
“Copahue is a volcano that has liquid sulfur in its crater. So, when the gas passes through, it soaks up as if it were a detergent that makes bubbles, although in this case they are small balloons of sulfur that remain floating on the surface and can be seen with a microscope”, details the researcher, who also directs the Institute. of Research in Paleobiology and Geology of the UNRN.
Thus, one of the purposes of the work they are carrying out is to see how much liquid sulfur influences the generation of eruptions. The specialists’ hypothesis is that the rise in temperature increases its viscosity and generates a plugging effect until the energy exceeds a threshold and is uncovered with an explosion.
In this regard, Paula Páez, a Master in Environmental Engineering, analyzes the dispersion, scope and consequences of Copahue emissions. “There are different types of gases and ash that the volcano emits, so we proposed to evaluate its impact on rain and snow. Water is an important resource in the area and we have been taking samples for three years now. For now, one of the effects of this phenomenon is its acidification”. In addition, other research is being carried out at the site that studies how rain and acidified snow impact plants and animals.
alert traffic light
According to the Argentine Mining Geological Service (Segemar), a scientific and technological body in charge of geological and mining information in the national territory, there are at least 39 volcanoes in the country that are considered active. In this sense, the Argentine Observatory for Volcanic Surveillance, which depends on Segemar, permanently monitors those changes that could announce an eruptive process and generates early warnings to mitigate the risk.
If the Andes Mountains and those located in Chile are taken into account, but whose eruption could have consequences in Argentina, the number of active volcanoes rises to 120. In fact, the last three alerts issued by the Observatory were for structures that are in the neighboring country.
In this regard, Segemar developed a Volcanic Technical Alert Traffic Light whose colors are green, yellow, orange and red. The first occurs monthly and is about those volcanoes that are at rest and do not pose any danger. In the second case, which represented the last three warnings, the report is biweekly and is issued when seismic activity, the emanation of fumaroles, explosions and ash fall increase. With the orange alert, the warning is daily and, in addition to the above signs, there may be an emission of lava flows. For its part, red is the most dangerous: volcanic activity is prolonged and the threat to populations is very high.
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