Chile’s National Geology and Mining Service has issued an orange alert for Nevados de Chillán, a complex of snow-capped stratovolcanoes located in the Ñuble region near the country’s border with Argentina.
The agency’s level-orange alert signifies a significant uptick in volcanic activity.
According to NASA’s Earth Observatory: “Like other historically active volcanoes in the central Andes, the Nevados de Chillán were created by upwelling magma generated by eastward subduction, as the dense oceanic crust of the Pacific basin dove beneath the less dense continental crust of South America. The rising magmas associated with this type of tectonic environment frequently erupt explosively, forming widespread ash and ignimbrite layers. They can also produce less explosive eruptions, with voluminous lava flows that layer together with explosively erupted deposits to build the classic cone-shaped edifice of a stratovolcano.”
According to Chile’s geology and mining agency: “The main volcanic hazards associated with the CVNCh correspond to lahars, debris flows and lava flows, channeled through the main valleys: Estero Renegado, Estero Shangri-La, Chillán River, Estero San José, Santa Gertrudis River, Gato River and Las Minas River . The generation of lahars configures the greatest potential danger for the population surrounding the volcano, given its proximity to the channels and the amount of snow and ice on the summits of the complex. Ash fall determined by the dominant wind direction.”
Ecuador contains one of the densest concentrations of volcanoes on the planet. At last count, 84 volcanic centers straddle the Andes mountains, which run through the country north to south. As many as 24 of those volcanoes are potentially active and some are covered in glaciers, which compound the threat of an eruption with the addition of ice and glacier debris. A history of major eruptions and recent volcanic activity, including on the glaciated stratovolcano Cotopaxi, has unnerved Ecuadorian citizens and prompted government action.
On April 19, the International Federation of the Red Cross and Red Crescent Societies (IFRC) issued an early action protocol (EAP) to ameliorate the health, livelihood, and food security impacts of ash fallout from volcanic eruptions on Ecuadorian communities.
The EAP is the result of a project, spearheaded by the German Red Cross, to coordinate forecast-based financing to reduce the impact of extreme natural disasters in 20 countries. Ecuador was selected to receive support for a volcanic ash fallout plan.
When a volcano erupts, there is often a period of unrest, precursor signals of an eruption, in which ash is spewed from the volcano. Ash fallout can affect health, livelihoods, and food security for people living in the deposition zone. Unrests can be prolonged events, like that of Cotopaxi in 2015, which lasted four months and did not result in an eruption – yet. Unrests can be longer, shorter, or there can be no sign of unrest at all.
The early action protocol cites its objective to “establish appropriate early action using volcanic ash dispersal and deposition forecasts that benefit the most vulnerable families in the most potentially affected areas.” The early actions identified were based on the ash fall produced by eruptions over the past 20 years, including that of Cotopaxi, which is located 31 miles south of Quito, the capital city of Ecuador. A major eruption would rain ash on the three million inhabitants of Quito and disrupt air travel.
The phases of early action for ash fall depend on the depth of forecasted ash deposition: distribution of health protection kits for ash fall between two and five millimeters, a livelihood protection package to protect livestock and harvested crops from ash fall between five and ten millimeters, and the addition of cash-based interventions for ash fall greater than ten millimeters.
Benjamin Bernard, a volcanologist at the Geophysical Institute of Ecuador’s National Polytechnical School (IG-EPN), works with the Ecuadorian Red Cross and the Red Cross Climate Center. According to Bernard, the objective of the project is to reduce the impact of extreme events based on scientific forecasts and early actions.
“This EAP is a significant improvement because in Ecuador, until this project, humanitarian financing was only for response to the emergency,” Bernard told GlacierHub. “It has already been proven in this project that early actions can significantly reduce the impact of extreme weather conditions and we hope that it will do the same for volcanic eruptions.”
In 2017, The Atlantic published an article titled “The ‘Anticipatory Anxiety’ of Waiting for Disaster,” which documented the trauma of Ecuadorians living in the shadow of Cotopaxi. Patricia Mothes, a volcanologist with Ecuador’s Geophysical Institute, told the magazine, “Of the five eruptive periods from 1532 to now—and this is number six—it always ends (or at least has) in a major eruption.”
Ahead of the anticipated major eruption, however, falling ash disrupts life for communities in the vicinity of Cotopaxi.
Ash fall from eruptions can have a significant health and economic impacts for downslope communities. “In previous events of ash fall, people have had to transport their animals to safe areas free from ash fall or have had to sell their cattle up to 70 per cent less than their normal commercial value, generating a negative impact on household economies,” the Ecuadorian Red Cross report reads. “In other cases, their animals died, which led to a serious impact on their economic stability. In these cases, affected households had to resort to bank loans that they continue to be unable to repay.”
But it’s not the lava or even the ash that worry those who live near glacier-clad Cotopaxi, The Atlantic reported, it’s the lahar—a superheated deadly slurry of mud, water, volcanic rock, ice, and other debris.
Cotopaxi poses dramatically different hazards to nearby populations, according to Mothes. When combined with hot ash and flowing rock, an eruption of a glaciated volcano can create a lahars, which are known to travel downhill at speeds of up to 200 kilometers per hour (120 miles per hour). Ecuadorian government has installed eruption warning systems to alert communities in lahar zones. The moment monitors detect seismic activity consistent with an eruption, automated sirens rouse communities downslope.
Ecuador is the only country with glaciers straddling the equator. Though Ecuador is seldom thought of as a glacier country, so prominently do glaciers figure in the nation’s landscape they even appear on its national flag.
Bolívar Cáceres is the head of Ecuador’s glaciers program within the country’s National Institute of Meteorology and Hydrology. “The Secretary of Risk of Ecuador has worked extensively on the matter, I believe we would be prepared,” he told GlacierHub on Ecuador’s readiness for an eruption. “The latent threat of Cotopaxi is there, waiting for the big event.”
Five students from Sheffield University traveled to Tien Shan Mountain Range in Kyrgyzstan to investigate the impact of climate change on a glacier that had never been studied before.
“Central Asia is one of the most threatened regions in the world to climate change, seeing some of the fastest rates of global glacial retreat,” said Sam Gillan, one of the leaders of the expedition. “There is currently a real focus on developing understandings of how climate change is affecting glaciers there, and we wanted to contribute to this developing field of research.”
Gillan and his colleague Alex Hyde were working on their undergraduate dissertation projects in the geography department at Sheffield University. Hyde says in the video that the idea for the trip came after a visit to Kyrgyzstan in 2017. He and Gillian wanted to study an actual glacier rather than working on a project in a lab. They soon narrowed down their topic to the Fedorovitch Glacier due to its relatively flat surface and accessibility.
Calum Sowden joined the expedition as a medic, Tom Drysdale as the group’s mountaineering advisor, and Louise Reddy as a research assistant.
The video documents the challenges of conducting research in such a remote location and highlights the rewards of field work. The team’s month-long data collection included measuring snow melt and temperature change.
Working at an elevation of 3,000 meters in such a remote location was challenging, mentally and physically, Reddy says in the video. “The hardest thing for all of us was the fact that the research requires you to do as much as possible,” he said. “The more often you take samples, the better the research will be.”
Check out the full video to see these young scientists at work—and find out what their favorite food was while isolated for a month in the mountains of Central Asia.
Check Out More GlacierHub Stories About Kyrgyzstan:
This week’s Photo Friday features two restless, glacier-covered volcanoes in Kamchatka, a peninsula lying on the Pacific coast of the Russian Far East.
The alert level for the Sheveluch and Ebeko volcanoes is currently code orange, meaning they are exhibiting “heightened unrest with increased likelihood of eruption” or a volcanic eruption is underway with “no or minor ash emission,” according to the Kamchatka Volcanic Eruption Response Team (KVERT).
The volcanoes could potentially emit ash plumes, which would impact a nearby airport as well as low-altitude domestic aircraft and international flights. Over 700 planes, transporting thousands of passengers, fly in the vicinity of Kamchatka’s volcanoes each day, according to KVERT.
Eruptions of glacier-covered volcanoes, such as Sheveluch and Ebeko, can create lahars, or mudflows, which sometimes threaten nearby communities. Lahars occur when hot water and eruption debris mixes with glacial water.
On August 14, 2015, Ecuador’s glacier-capped Cotopaxi erupted for the first time since the 1940s. A billowing plume of ash rose early in the morning and grew through the day, reaching heights of over three miles. Two small eruptions rained ash on the southern outskirts of Quito, Ecuador’s capital 45 kilometers from the volcano. These dramatic events rattled the country and punctuated a period of seismic and low-level volcanic activity that lasted from April to November 2015.
Recently, scientists at Ecuador’s Instituto Geofísico Escuela Politécnica Nacional (IGEPN) analyzed both the physical properties of the episode and the institutional and community responses of this “dry run,” yielding information that will help Ecuador prepare for future events. Lead author and IGEPN geologist Patricia Mothes told GlacierHub that among the most important lessons learned from the period of restlessness were that “changes can occur very rapidly,” and that certain seismic trends and deformation of the volcanic cone will act as precursors to actual eruption.
The report found that over the seven months of earthquakes, degassing, ground deformation, glacial melting and plumes towering over the landscape, the activity level of the episode actually remained relatively low, at two out of eight on the Volcanic Explosivity Index.
Nevertheless, the impacts of the activity were manifold. Heat from the rising magma, in tandem with the layer of dark ash that formed on the glaciers, increased melting and formed new crevasses. People donned masks to avoid breathing in the ash, which damaged crops, sickened livestock, and lowered visibility on the roads for people in transit across the country. Some residents hastily sold their land and livestock or abandoned them entirely. The net effect was to depress the local economy.
With this geophysical unrest came unrest to those living near the volcano. The controversial President Rafael Correa declared a state of emergency, and thousands of residents of nearby villages evacuated to safer areas. After weeks to months of displacement in shelters and other towns, some returned to their homes, but recovery was slow and incomplete. In addition to economic harm, the volcanic activity had psychological dimensions. The Atlantic reported that people living in the risk zone experienced sleeplessness, anxiety, depression, and Post Traumatic Stress Disorder.
The most intense threat to Ecuadorians was the potential of lahars, slurries of mud and melted snow and ice that can flow for tens of miles and devastate landscapes. The geologic record shows that in each major eruption, most recently in 1877, Cotopaxi has spawned major lahars on each of its flanks. During the 2015 event, glacial melt formed small lahars that sometimes covered the road to the volcano.
In the event of a more major eruption, glacial outburst floods could occur, according to Mothes. “If impacted by hot pyroclastic flows that would come out of the summit crater and careen down the steep flanks, the glaciers would be greatly eroded, ripped up, and much internal glacier water would likely be released,” she told GlacierHub. During the eruption of 1877, between five and ten meters of ice melted, and giant lahars formed. In the event of an eruption in the future, “the only mitigation scheme is to have people go to higher ground, out of the areas to be potentially affected by lahars,” said Mothes.
Communication surrounding the eruption events at the science-society interface was fraught, according to the IGEPN report. Though the agency released three updates daily, misinformation spread broadly through social media, causing panic. In response, emergency services and the IGEPN formed a “vigía” (“look-out” in Spanish) network of observers near the volcano, who disseminated observations of Cotopaxi on local radio stations.
Though the 2015 period of restlessness was traumatic to those that lived through it, the authors note that the landscape and local residents have recovered from Cotopaxi’s eruptions several times throughout history. Reports from as far back as the 16th century indicate that Cotopaxi typically “warms up” slowly before erupting. At present, the IGEPN has over seventy-five scientific instruments on the volcano, continuing monitoring that began in 1986. “At the moment, there is nothing to suspect,” said Mothes.
The report concluded, “Overall, the volcano’s manifestations served as a warning to everyone to keep attentive of Cotopaxi’s capacity to cause destruction and possible severe ruin.” With a major eruption likely to be forthcoming, the authors called such a warning “benevolent.” Ecuador will continue to await the eventual eruption.
Lahars, or mudflows from the eruptions of glacier-covered volcanoes, are a threat that the communities of Skagit Valley in northwest Washington live with. These destructive mudflows can be triggered during volcanic eruptions when hot water and debris rush downslope from the volcano and mix with glacial water. A recent study from the Journal of Applied Volcanology by Corwin et al., identifies ways to improve hazard management and community preparedness in Washington’s Skagit Valley, home to Mount Baker, the second most glaciated volcano in the Cascade Range, and Glacier Peak, the second most explosive. The highly populated communities within Skagit Valley remain especially at risk for dangerous mudflows since both Mount Baker and Glacier Peak are considered active lahar hazard zones.
All five of Washington’s Cascade Range volcanoes are active. These volcanoes are especially dangerous because in addition to flowing molten lava and spewed ash that can destroy everything downhill, volcanoes with snow and ice at their peaks can create additional perils. Heat from the eruption can melt the snow or ice that has accumulated, create mud, and pour down narrow mountain valleys. This mixture of water and rock fragments that flows downslope of a volcano into a river valley has dangerous repercussions for communities like those in the Skagit Valley.
While lahars can be visually stunning when the volcanic material interacts with glaciers — see the remarkable images in GlacierHub’s recent article on these events in the Kamchatka Peninsula in Far East Russia— lahars can cause extensive damage to the built environment as boulders destroy structures and mud buries entire communities. Moving laharsappear as a roiling slurry of wet concrete and can grow in volume as they incorporate everything in their path — rocks, soil, vegetation, and even buildings and bridges.
Corwin et al. determined that a crucial disaster risk management strategy for lahar events is “whole community” training programs, which emphasize household preparedness and help disaster responders better perform their duties. Since lahars can cause widespread damage to the surrounding environment, it is important for community members to understand how to address the hazard before it occurs.
The focus of the research was on the ascription of responsibility on preparedness and the influence of professional participation in hazard management on household preparedness and risk perception. Disaster response professionals know the best household preparedness measures, yet they sometimes fail to implement these measures in their own households. The study found that this may be a result of professional disaster responders being out in the field during a disaster, instead of in their homes.
Even more surprising, response professionals failed to interpret local volcanic hazard maps more accurately than laypeople. There could be several reasons for this that need to be explored in a subsequent study, but as Kimberley Corwin, a geoscientist and the leading author of the study, explains, it could be because “people in both groups drew on outside information such as what they remembered or learned about the 1980 Mount St. Helens eruption.”
When asked by GlacierHub about her familiarity with lahars, Corwin described her closest experience with an active volcano in Chile’s March 2015 Villarrica volcano eruption. Corwin was in Pucón, Chile, for a volcanology course with Boise State University. The group of academics arrived two weeks after the main fire fountain event, which triggered a lahar. There was still active ash venting in the area.
“While we were there, the alert levels in the town were elevated and a 5-kilometer exclusion zone was set up around the vent,” Corwin explained. “It offered a great opportunity to observe the reactions of locals, tourists, and officials.”
Corwin’s further research found that preparedness measures are crucial in areas that are prone to natural disasters, as they can help professional responders and other community members protect themselves and their families.
A video of a 2003 lahar event in East Java, Indonesia, at the Semeru volcano (Source: adripicou/YouTube).
In the Skagit Valley, nearly all the community members correctly identified that lahars pose a risk to the region. However, when questioned about their confidence level on how to respond to a lahar, the participants demonstrated decreased self-assurance. They answered by saying that they have higher confidence when responding to floods, as these natural events occur more frequently than lahars.
Some recommendations for implementing “whole community” training programs involve increasing community participation in hazard management, identifying where community members can access hazard information, and providing instructions on how to interpret this information. Overall, these recommendations would increase household preparedness and allow professional responders to successfully complete their tasks without worrying about the safety of their families back home. In this way, community members would reclaim responsibility for their personal safety, and professional responders could feel more comfortable responding during a hazardous lahar event.
From Xanterra: “Just 150 years ago, 150 glaciers graced these spectacular alpine summits. Only 25 remain large enough today to be considered ‘functional,’ say scientists who expect the park’s glaciers to vanish by 2030, with many disappearing before that. People heeding the advice to visit soon will find a variety of national park lodging and dining spots that are making environmental stewardship part of the park experience.”
From Journal of Applied Volcanology: “As populations around the world encroach upon the flanks of nearby volcanoes, an increasing number of people find themselves living at risk from volcanic hazards. How these individuals respond to the threats posed by volcanic hazards influences the effectiveness of official hazard mitigation, response, and recovery efforts. Ideally, those who are aware of the hazards and concerned should feel motivated to become better prepared; however, research repeatedly shows that an accurate risk perception often fails to generate adequate preparedness… This study explores the barriers that people in the Skagit Valley of Washington face when deciding whether or not to prepare for lahars as well as the impact of participation in hazard management on household preparedness behaviors.”
Read more about Washington’s lahar preparedness here.
How Changing Climate Affects Ecosystems
From Environmental Research Letters: “Climate change is undeniably occurring across the globe, with warmer temperatures and climate and weather disruptions in diverse ecosystems (IPCC 2013, 2014). In the Arctic and Subarctic, climate change has proceeded at a particularly breakneck pace (ACIA 2005)… However, climate warming is forecast to be even more extreme in the future. In order to predict the impacts of further global change, experiments have simulated these future conditions by warming the air and/or soil, increasing CO2 levels, altering nutrient fertilization, modifying precipitation, or manipulating snow cover and snowmelt timing (Elmendorf et al 2015, Wu et al 2011, Bobbink et al 2010, Cooper 2014). Changes in biodiversity at high latitudes are expected to have profound impacts on ecosystem functioning, processes, and services (Post et al 2009).”
Read more about how changing climate affects ecosystems here.
The Kamchatka Peninsula in Far East Russia is an isolated region known for its glacier-volcano interactions that can lead to powerful natural disasters— and also, visually stunning images when lava impacts ice. One of these volcanoes, Sheveluch, has been erupting in recent weeks, creating local hazards. The volcano’s ash cloud, for one, threatens to disrupt air traffic in the region.
In total, Kamchatka is home to 160 volcanoes, 29 of which are currently active. These volcanoes— six of which are designated UNESCO World Heritage sites— are tall and far enough north to harbor glaciers. As such, they are associated with lahars, devastating mudslides down the slopes of a volcano triggered by an eruption and melting glaciers. These mudslides move quickly, destroying most of the structures in their path.
Avachinsky is one active volcano in the region that is covered in glaciers, placing the surrounding region at a greater risk for lahars. Avachinsky is classified as a stratovolcano, which is a volcano that has been built up by alternate layers of lava and ash. It is the volcano closest to the state capital Petropavlovsk-Kamchatsky.
“The Avachinsky volcano is glacierized, and the melting of ice poses a serious lahar threat the next time the volcano is active,” Ben Edwards, a volcanologist and professor at Dickinson College, warns. Edwards explained to GlacierHub that there are many deposits mapped out that are indicative of past lahars.
Previous lahars in the Kamchatka Peninsula have been devastating with high human death tolls. The Nevado del Ruiz volcano in Colombia, for example, erupted in 1985, producing a lahar that killed 23,000 people.
“They are incredible forces of nature and also brutally destructive and deadly,” said Janine Krippner, a PhD candidate in volcanology and remote sensing at the University of Pittsburgh, in an interview with GlacierHub.
The Klyuchevskaya Sopka stratovolcano is the highest mountain on the peninsula and the highest active volcano in Eurasia. In November 2016 and more recently in January, the volcano spewed ash six kilometers above sea level. Such an ash cloud can disrupt international travel. Klyuchevskaya has produced notable lahars in the past including one particularly damaging one in 1993, according to Edwards.
The position of a glacier on a volcano can influence the risk of a lahar. However, there is still much research needed on past lahars at Klyuchevskaya to better understand risk, notes Edwards.
“Many volcanoes have glaciers up high, but those close to Klyuchevskaya are on the western lower flank,” explained Edwards. “There have probably been some interactions and definitely lahars generated from historic flows. But these eruptions have not been well documented.” Higher regions, which tend to be cooler and moister, are more likely to form glaciers.
Sheveluch Peak is a very active volcano, and the largest on the peninsula at 1,300 cubic kilometers in volume. Many glacier-volcano interactions have occurred at the location, releasing great quantities of steam and creating fantastic imagery for photographers.
Similar volcano-snow interactions also take place elsewhere on the peninsula, especially during the winter, according to Edwards. “We saw spectacular examples during the 2012-13 Tolbachik eruption,” he said.
The World Heritage website, which features several of the Kamchatka Peninsula volcanoes, makes special note of the “dynamic landscape of great beauty” created by the interplay of active volcanoes and glacier forms. In addition, the peninsula has a wide diversity of species including brown bears, sea otters and the world’s largest variety of salmon fish. It is also known for a wide variety of birds from falcons to eagles that are attracted to the spawning salmon populations.
“Volcanism probably also interacted with regional ice caps during the Pleistocene,” Edwards explained. “But very little work has been done on this in Kamchatka so far. There is room for this type of work in the future.”
Volcanoes can help glaciers in one way: the ash and soot they emit reflects sunlight away from Earth, helping to cool the warming climate. However, volcanoes currently pose significant risk from lahars to destructive lava and ash. Scientists must continue to observe volcanoes to help reduce these hazards and improve early warning systems.
The Volcanic and Seismological Observatory of Manizales has recently conducted several workshops on volcanic risk with communities in the vicinity of Nevado del Ruiz, a glacier-covered volcano in Colombia that showed signs of renewed activity earlier this year.
The workshops prepare communities to react to volcanic hazards like ash and lahars, the latter of which can occur when lava flow mixes with the icy temperatures of glaciers. Locals participate in focus groups and model experiments to better understand the volcanic risks in their community.
“Communication Strategy of Volcanic Risks,” is enacted in conjunction with the Colombian Geological Service, the National Unity of Disaster Risk Management, and other regional and municipal agencies. Check out some photos of the workshop, courtesy of the Observatory, below.
Click here to “like” the Observatory’s Facebook page and to see more photos of the project.
The glacier-covered Volcan del Ruiz in Colombia has shown signs of renewed activity in the last several days, following a shallow earthquake of 3.0 on the Richter scale on June 22, associated with fracturing of rock within the volcano. The Colombian Geological Servicerecognized this fracturing as a sign of possible movements of magma that could lead to an eruption of lava. Tom Pfeiffer, a German volcanologist, suggested that the earthquake was “possibly caused by increased magma pressure inside the volcano’s upper storage system.”
Earlier this week, on June 27, the volcano released an ash cloud, reaching 1,800 meters above the summit. A second emission on June 28 attained a height of 850 meters. Its volume was sufficient to threaten aircraft in the region, which led to the sudden closure of the regional airport in Manizales, 25 kilometers to the northwest.
One local resident released alerts on Twitter, directing people to close windows and to wear face masks as protection against the ash. In a second tweet, included below, she indicated that the warning level had been raised from yellow to orange, “alerta naranja,” though official sources in the Colombian Geological Service and the regional Risk Management Unit wrote to assure the public that the warning level remained at yellow.
On its Facebook page, the regional Volcanic and Seismological Observatory released a video of the most recent eruption, taken on its webcam:
As GlacerHub explained in a recent post, the presence of glaciers on the volcano’s summit creates the risk of destructive debris flows known as lahars. The very rapid melting of ice caused by contact with molten lava can cause floods to rush down the mountain’s slopes, carrying large quantities of ash, rock and soil to populated areas. An eruption of the volcano in 1985 led to over 23,000 deaths.
The Colombian authorities and local citizens are monitoring this situation closely. If an eruption is likely, the municipalities in the region will receive warnings. GlacierHub will report on any significant intensification of the volcano’s activity.
A large glacier-capped volcano in Colombia, the Nevado del Ruiz, has shown significant activity in recent weeks, raising fears of destructive mudflows known as lahars. Photographers recorded ash emissions starting on May 19. The Colombian Geological Service noted volcanic activity and tremors at the volcano early on the morning of May 22. The 5,321 meter high stratovolcano, located in Colombia’s Los Nevados National Park, initially emitted a 1,300-meter plume of ash at 2:35 a.m., followed by a second 2,300-meter plume at 5:51 a.m. causing the temporary shut down of La Numbia Airport. Activity continued through May 25, when an additional ash emission occurred at 7:00 a.m. Though the volcano has not erupted, conditions remain unstable and the possibility of further activity is being closely monitored, particularly since the seismic activity suggests the movement of magma in the volcano, raising the possibility of an eruption. The Colombian Geological Service has set the warning level at yellow.
The volcanic activity at Nevado del Ruiz sparked concern from the scientific community, as the volcano is historically known for its deadly eruptions. When the Nevado del Ruiz erupted in November of 1985, it caused what is today considered the worst volcanic disaster in South America’s history, and the fourth worst in the world. Over 23,000 Colombians were killed, with the majority of fatalities in the town of Armero. However, it was not the eruption itself that caused such extensive damage—the glaciers at the summit of Nevado del Ruiz are what made the event so deadly.
“Glaciers and volcanoes can be a particularly hazardous combination,” commented Jerry McManus of Columbia’s Lamont-Doherty Earth Observatory in an email to GlacierHub. “The snow and ice provide a ready source of water for the potential generation of destructive lahars during eruptions.”
Lahars, rather than lava, are what leveled the town of Armero and caused the resulting fatalities. Lahars are large mudflows caused by summit glacier melt during an eruption. The combination of water and volcanic rock debris, known as pyroclastic material, creates a material similar to liquid concrete. The 1985 eruption of Nevado del Ruiz created four lahars, which flowed down the volcano at speeds up to 30 kilometers per hour. Armero, located 48 kilometers from the base of the volcano, did not have time to prepare or evacuate. In the aftermath of the disaster, the Colombian government was strongly criticized for underestimating the dangerous impacts of the relatively small eruption despite warnings from volcanologists.
The population of the region has grown over the past three decades, putting more people at risk if an eruption is triggered. Over 500,000 Colombians live within 30 kilometers of the volcano, well within the range of a lahar—significantly closer than Armero. With the disaster still fresh in the minds of the Colombian government and scientific community, the current activity at the Nevado del Ruiz is being more closely monitored.
Several recent events suggest that a set of glacier-covered volcanoes in the southern Chilean region of Bío-Bío, which have been showing increasing activity since December, may be likely to erupt. The three mountains, known as the Nevados de Chillán, reach over 3200 meters in elevation, and have a set of glaciers totaling over 2 square kilometers in area on their summits. They have a long record of eruptions, with historical documentationfrom the 17th century. Radiocarbon evidence records eruptions that took place about 8000 years ago.
The Nevados de Chillán complex, which averaged about one eruption a decade during the 19th and 20th centuries, had been relatively quiescent since an eruption in 2003. Sticking roughly to that schedule, the complex began to show signs of returning to activity with an earthquakein February 2015 which registered 3.2 on the Richter scale. The Chilean National Geology and Mining Service (SERNAGEOMIN) maintained the volcano warning at the lowest level, green, until 31 December, when it issued a yellow warning, signaling an intermediate level of danger. This shift was prompted by the appearance of a new gas vent on 8 December and by a series of over 2000 small seismic events, all under 2.0 on the Richter scale, throughout the month, which indicated the fracturing of solid rock and the upward movement of magma beneath the surface.
This activity has picked up in January, with the openingof a second new vent on 8 January, accompanied by a 2.9 earthquake and a cloud of ash. SERNAGEOMIN and the National Office of Emergencies (ONEMI) installedtwo webcams near this vent on 27 January. Providing these cameras with material to record, new clouds of ash appeared on 29 January. On 30 January, a crater, about 25-30 meters in diameter, appearednear the other new vents, with gasses, ashes and occasional blocks of cooled lava emerging from it. Temperatures at the summit were about 125º C, which was consistent with ongoing hydrothermal activity but did not suggest that magma, typically closer to 1000 º C in temperature, was approaching the surface. Taken as a whole, these new activities led ONEMI to create a 2-km zone around the new craters from which people are excluded. The local sense of concern was increased by the wide availability of images from the new cameras and from an impressive thunderstorm on 31 January, as shown below:
Dave McGarvie, a volcanologist with considerable experience in ice-covered volcanoes, has been working around Chillán since 2001. In his blog, he offers this overview of the situation:
What makes me think that this unrest is likely to lead to an eruption? Well there are two main reasons.
Firstly, there’s clearly been a new heat source introduced into the plumbing system beneath the volcano, and this had drilled a new pathway to the surface leading to bursts of heat escaping through a new vent. This heat source is almost certainly due to magma rising up in the plumbing system. And at the moment there’s a ‘vent-cleaning’ phase in place, with bursts of heat interacting with water contained within the cone (Hydrothermal). There are probably magmatic gases involved as well. These energetic outbursts are cleaning out material in the developing conduit, and possibly also pulverizing (fragmenting) material being blown out.
Secondly, this new vent has developed on the youngest cone at this volcanic complex, which has developed through a long series of eruptions, punctuated by time gaps of a few years to decades.
McGarvie’s assessment is that an eruption in the near future would probably be small, though it could include significant volumes of lava as well as of gases and ashes. He notes that the snow cover on the mountain is relatively small at this time of year, the austral summer, but that the risk of melting snow and glacier ice cannot be excluded. SERNAGEOMIN produced a map in 2012 that indicated the zones of danger from lahars (volcanic mudflows), which extend 40 km from the volcanoes through the foothills of the mountains and of local authorities into valleys with farms and town. Local officials could use these maps to organize evacuations if a large eruption occurred.
However, the summer season brings another risk to the area: fires. A brushfirein the area on 31 January threatened to grow large, but was controlledafter several hours. On 1 February, the National Forestry Corporation (CONAF) sent three helicopters to combat a large and rapidly-moving forest fire near the mountain. With the assistance of the lumber company Masisa and four local fire departments, CONAF was able to extinguish the blaze, which closed local roads. The movement of lava down the mountain could create a large series of fires which would prove more difficult to control, especially if the current heat wave continues.
The coming weeks will provide more information about the activities of this glacier-covered volcano complex. A recent video, with dramatic footage of a sudden burst of ash and an audio recording of sustained deep rumbling, offers a suggestion of what the start of an eruption might be like.