Latest Specific Risk Ranking of Active Volcanoes in Chilepublished by the National Volcanic Surveillance Network of the National Geology and Mining Service (Sernageomin) in 2023, showed 87 volcanic systems considered geologically active. Of those, 14 have a higher level of risk, both due to their history of eruptions and the exposed population, and the majority of them are in the southern part of the country, in the regions of La Araucanía, Los Ríos and Los Lagos.
Although the active volcanos are distributed throughout almost all regions of the country, when considering the 14 with a specific risk level considered “very high”, the list is headed by volcano Villarricalocated on the edge of the Araucanía and Los Ríos Regions. In that same territory are the volcanoes Llaima and Lonquimayin the first, and the Carrán-Los Venados, Mocho-Choshuenco and Puyehue-Cordón Caullein The rivers. This last complex is also shared with the Los Lagos Regionwhere there are alsol Calbuco, Chaitén and Osorno.
Franco Vera, head of Sernageomin’s Geology and Volcanic Systems Hazard Unit, explains that The ranking classifies active volcanoes according to their specific risk level. “It is important to note that two main factors are considered: the degree of danger, that is, the impact and probability of occurrence of a volcanic process (for example, a volcanic alluvium or lahar); and The exhibition, which contemplates the number of people who are threatened by danger. Therefore, A volcano with a higher level of risk is one with a greater number of exposed people and critical infrastructure in volcanic danger zones.“he maintains.
What happens in the area with the most dangerous volcanoes?
According to Sernageomin, the volcanoes of central Chile and up to Aysen Regionare part of the Southern Volcanic Zone of the Andes. There are those that involve the greatest risk.
Daniel Díaz, academic at the Department of Geophysics of the FCFM – U. de Chile and researcher at the Instituto Milenio Ckelar Volcanes, explains that the southern Andes (which extend from the Metropolitan Region to Los Lagos) is a volcanic area that not only stands out nationally, but is also very productive on a global scale. “There is no single reason, it has to do with properties that the crust has in this place and that generate a large amount of magmatism, therefore, a large number of volcanoes,” he indicates.
The process of subduction or sinking of the Nazca plate under the South American plate releases fluids, water with a lot of pressure, which in its rise produces magmatism, which manifests itself in volcanism.
“Generally, The southern area of Chile differs from the northern area by having a thinner earth’s crustwhich implies that the magmas travel less distance to travel from their point of generation, under the crust, to the surface,” says Franco Vera, from Sernageomin.
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Another differentiating factor is the presence of Liquiñe-Ofqui Fault Systema structure more than 1,000 km long, which runs from the regions of the Biobío to Aysén. “This large structure facilitates the rise of magmas, so it could be one of the factors that explains a greater eruptive recurrence in southern Chile. In any case, In the north of the country we also have volcanoes with high recurrence, such as the Láscar volcano.just as in the southern zone of Chile we have at hudson volcanowith recurrent historical eruptions,” he emphasizes.
The peculiarities of an active volcano
Of the 87 volcanoes currently considered active in Chile, in very few cases noticeable signs are seen. An active volcano is one that today shows signs of internal activity recorded by instrumentsbut also the one who has had any rash recentlythat is, in the last 10 thousand years.
“Volcanoes are quite old by our standard of time. A volcano can be 500 thousand years old, so the last 10 thousand years are recent activity in its history, they are eruptions in their last stage of development. In Chile we have enough of those, with historical eruptions in the last 500 years”says Díaz.
Gabriel Ureta, researcher at the Research Center for Integrated Disaster Risk Management (CIGIDEN) and Ckelar Volcanes, adds that volcanoes have different behaviorsthere are volcanoes that clearly demonstrate their activity with the emission of gases or earthquakes generated by the movement of magma, for example, while others do not demonstrate their activity, but are still active.
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“Hence the importance of carrying out volcanic monitoring and, above all, study the record of volcanoes’ pastsince by understanding how a volcano behaved in the past, it is possible to understand how it may behave in the future,” he emphasizes.
Sources and references of the news:– Complete Sernageomin Ranking
