Chile is not home to just five or nine active volcanoes: it has almost 90 massifs that could erupt unpredictably and endanger nearby communities. Some more dangerous than others, the volcanoes of this South American country are the subject of research, monitoring, and still surprises, as was the case a few decades ago with the Chaitén volcano, which had a violent and unexpected eruption.

 

In 2008, Chile had few instruments, and only three volcanoes were being monitored. Little (almost nothing) was known about the Chaitén volcano, and its activity surprised the scientific community and government agencies.

 

The disaster caused by the volcanic activity led to the evacuation and relocation of an entire town in Chilean Patagonia. This episode marked the beginning of a new era in volcanic research and monitoring in Chile.

 

"The Andean volcanic arc, particularly in Chile, is one of the most extensive in the world. According to the latest national ranking, the number of active volcanoes—those with proven activity in the last 10,000 years or with visible signs of activity, such as deformation, seismicity, and fumaroles—is 87. In other words, Chile is on par with countries such as Japan, Indonesia, and Alaska, which have the highest levels of volcanic activity in the world," explains Álvaro Amigo, head of Chile's National Volcanic Surveillance Network (RNVV) and the National Geology and Mining Service (Sernageomin).

According to Amigo, around 35 volcanoes have erupted with varying intensity since the 16th century, and these eruptions have been documented since the Spanish arrived to these lands. 

 

"Alonso de Ercilla's La Araucana describes the Villarrica volcano as active. Additionally, there have been very intense eruptions with large volumes of material ejected in the 20th century, such as from the Quizapu volcano in 1932, the Hudson volcano in 1991, the Chaitén volcano in 2008, the Puyehue-Cordón Caulle volcano in 2011, and the Calbuco volcano in 2015," he says.

 

The Specific Risk Ranking of Active Volcanoes in Chile expresses this volcanic threat in Chile as the sum of the hazard and exposure factors for communities and critical infrastructure, such as roads, bridges, and power lines.

 

Volcanoes are prioritized with a classification that allows more resources to be allocated to those that pose the greatest risk. This is due to the difficulty of providing volcanic monitoring for all active volcanoes in Chile.

 

According to a 2021 Sernageomin report published in the international scientific journal Volcánica, about 5% of Chile's continental territory is susceptible to direct volcanic event impacts, such as lahars and pyroclastic flows. Up to 35% of the territory could be affected by ashfall.

 

"Although few people live within a 10 km radius of an active volcano, 60% live within a radius of less than 100 km. Since the 19th century, at least 15 eruptions have resulted in loss of human life on the Lonquimay, Llaima, Villarrica, Mocho-Choshuenco, Carrán-Los Venados, and Hudson volcanoes," the report states.

 

As of 2020, a total of 45 volcanoes are monitored in real time, from the northern tip of Chile to the Aysén Region. This monitoring allows for the anticipation of possible adverse scenarios. "Volcanic processes involve risk because they generate phenomena that threaten the population and infrastructure," says the Sernageomin expert. "This means that Chile must invest in both scientific research and volcanic surveillance."

 

"Early warnings can be issued to populations at risk, enabling authorities to make informed decisions and develop adequate risk management strategies. This involves mapping areas of high risk and creating hazard maps to inform land use planning around Chile's most active volcanoes," says Luis Lara, a professor at the UACH Institute of Earth Sciences.

 

He points out that, although populations are not always settled in close proximity to volcanoes in Chile and around the world, critical infrastructure and economic activities, such as tourism, must be protected from volcanic eruptions.

 

Lara adds, "Systematic observation of active volcanoes reduces uncertainty, provides a diagnostic tool, and offers security to those who live or work around volcanoes."

Although Chile's volcanoes are a true natural paradise for volcanology, studying and monitoring them is complex, warns Felipe Aguilera, director of the Millennium Institute of Volcanoes and professor at Andrés Bello University. Aguilera says, "Volcanoes are dynamic systems that require systematic observation. This includes not only instruments, but also terrain observation and sampling over a large area. Volcanoes are difficult to access, and there are adverse weather conditions and high altitudes. This means that volcanic research and monitoring require significant investments of time and resources from institutions."

 

Sernageomin agrees, as continuous volcanic monitoring requires proximity to volcanoes and maintaining stations at high altitudes in conditions of snow, ice, and wind, which poses a significant engineering challenge.

 

"The key is to have a series of stations that allow for redundancy. That is, if the signal from one station fails, you can rely on another. Ideally, you would have telecommunications with multiple data delivery routes and satellite transmission," says Álvaro Amigo.

 

However, experts agree that the entire monitoring system requires multidisciplinary work. Varied monitoring and study of active volcanoes are needed to understand internal and surface changes in order to anticipate volcanic activity.

 

"Although eruptions are still unpredictable, volcanic surveillance allows us to detect changes in a volcano that could trigger an eruption weeks or months in advance, enabling us to make important safety decisions," says Luis Lara.