nevado del ruiz eruption 1985 case study

Benchmarks: November 13, 1985: Nevado del Ruiz eruption triggers deadly lahars

by Bethany Augliere Thursday, October 20, 2016

The 1985 eruption of Nevado del Ruiz in Colombia unleashed deadly lahars that swept through Armero, killing 20,000 people in that town alone. Credit: U.S. Geological Survey.

By Bethany Augliere

On Nov. 13, 1985, at a little after 9 p.m. local time, Nevado del Ruiz, a volcano about 130 kilometers from Colombia’s capital city of Bogotá, erupted, spewing a violent mix of hot ash and lava into the atmosphere. Less than three hours later, the earth rumbled as mudflows towering nearly 30 meters high swept through the countryside, several villages and eventually the town of Armero, where it killed 70 percent of the town’s residents. All-told, these mudflows, called lahars, killed more than 23,000 people.

Although it wasn’t considered a large eruption, heat melted snow and ice from a glacier capping the volcano and unleashed three lahars — a mixture of rock, volcanic debris, mud and water. The lahars roared down the volcano’s flanks at 30 kilometers per hour, picking up everything in their path, including trees and vehicles, as well as sediment and water from the rivers whose paths they followed. Ultimately, the lahars pulverized and entombed the towns in their wake. The next day, several more eruptions occurred.

The 1985 eruption of Nevado del Ruiz was Colombia’s worst natural disaster, the second-deadliest volcanic disaster of the 20th century (behind the 1902 eruption of Mount Pelée in Martinque) and the fourth-deadliest in recorded history.

In many ways, the eruption did not come as a surprise, wrote Barry Voight, then a geologist at Penn State University, in an analysis of the event. But, despite that, emergency management failed, causing unnecessary loss of life.

In the wake of the tragedy, two agencies — the U.S. Geological Survey (USGS) and the U.S. Agency for International Development’s Office of U.S. Foreign Disaster Assistance — came together to launch the international Volcano Disaster Assistance Program ( VDAP ) to track and monitor the world’s 1,550 potentially active volcanoes. Since its inception 30 years ago, VDAP has aided in more than 30 international crises, including the 2007 eruption of Nevado del Huila in Colombia, during which 4,000 people were safely evacuated.

“Ruiz is an absolutely seminal event in modern volcanology by virtue of demonstrating the hazards of long-reaching lahars from snow- and ice-clad volcanoes,” says Jeffrey Marso , a geologist with USGS and VDAP team member who went to Colombia in the days after the eruption. “We now know,” he says, “that a relatively small eruption on a high snow- and ice-clad volcano can produce lahars that threaten populations many tens of kilometers away.”

Path to Eruption

The summit crater of Nevado del Ruiz in late November 1985. Credit: U.S. Geological Survey.

Nevado del Ruiz is a large stratovolcano, similar to Washington’s Mount St. Helens and Mount Rainier, reaching more than 5,300 meters above sea level and topped by glaciers. “Nevado” means “snow-capped.” It’s one of the northernmost volcanoes in the Andean Volcanic Belt, a volcano chain running along the western coast of South America. Ruiz is the second-highest volcano in Colombia and sits in the Los Nevados National Park, which is home to seven other volcanoes.

In recorded history, Ruiz had two notable eruptive events. In 1595, three Plinian eruptions killed 636 people when a lahar swept down the nearby river valleys. In 1845, 250 years later, mudflows again flooded the upper valley of the Lagunillas River, killing more than 1,000 people.

Ruiz began stirring again nearly a year prior to the 1985 eruption, with early activity marked by earthquakes and fumarolic activity. In November 1984, climbers on the mountain reported gas emerging from the summit crater. In December, three earthquakes were felt within 20 to 30 kilometers of Ruiz. This activity continued into the next year.

So, in early 1985, emergency planning began. Geothermal researchers for the Central Hidroeléctrica de Caldas (Chec) visited the summit in January and noticed a new pit in the bottom of the crater had developed. In response, a civic committee formed in the closest large city, Manizales, with the support of Chec and local government, to monitor Ruiz. But, on Feb. 23, the region’s only seismograph broke.

In March, three geologists, including John Tomblin, a seismologist from the United Nations Office of Disaster Relief, visited the area at the request of Colombia’s civil defense agency. “The abnormal activity at Volcán Ruiz corresponds to typical precursory events for an eruption of magnitude,” Tomblin concluded, after witnessing vapor columns hundreds of meters high. He recommended the immediate installation of a seismograph and the preparation of a hazard map.

In the meantime, the Colombian Institute of Geology and Mining (INGEOMINAS) requested seismographs, other equipment and technical expertise from local companies as well as several countries, including the U.S., Costa Rica, Ecuador and Mexico. A Colombian electric company and Costa Rica sent seismographs and some other equipment, and USGS sent additional equipment to help operate the seismographs. The USGS Deputy Chief for Latin America wrote in a note to the United Nations Disaster Relief Organization: “The opportunity is clear, and it is unfortunate that we can spare no one from the Hawaii or Cascades Observatories. … If the volcano is to blow, let us hope that both we and the Colombians are prepared.”

On Aug. 8, the Swiss Disaster Relief Corps and Swiss Seismological Service sent seismologist Bruno Martinelli to provide technical support. The four seismographs sent by Costa Rica and the Colombian electric company had been poorly located, he noted in written communication. Once they were relocated, he wrote, “the seismic system could be considered to be suitable for monitoring the volcano.”

On Sept. 11, Ruiz blew gas and steam in a phreatic eruption for seven hours, but no magmatic eruption followed. It caught the attention of the government, however, which began to develop a response plan. Scientists began working to develop a draft of a volcanic hazard map. The dangers of lahars were obvious. Martinelli viewed the map before leaving and wrote: “The danger of lahars, especially along the Rio Azufrado and Lagunillas, was the guiding theme of this work.”

On the night of the deadly eruption, everything should have been in place to evacuate. Before leaving Manizales in September, Martinelli commented that he “was convinced that everything would be done to limit the possible damage.”

The Devastation of Armero

Lahars devastated the region, destroying everything in their paths: homes, agricultural fields, schools and roads. Credit: U.S. Geological Survey.

At 3 p.m. on Nov. 13, 1985, Ruiz sent up steam and gas in another phreatic eruption. Then it settled, and the rain started. This had happened before without a major eruption and “there was no clear instrumental indication in the following hours that a bigger eruption was coming,” Marso says. “In general, the Colombians knew an eruption was possible, but didn’t have hours and hours of warning that it was coming,” he says. Local authorities met, but with no way to forecast the next eruption, no clear, authoritative evacuation was ordered. Six hours later, the situation turned serious when a magmatic eruption started. Once an eruption starts, Marso says, “there’s a fixed time frame for evacuation — at that point, the clock was ticking.”

In Manizales, scientists and officials detected the eruption as soon as it began at 9:09 p.m. However, Marso says, “it turns out there was just too little time.” After a 20-minute magmatic eruption, it took just an hour for the first lahar to reach the closest town of Chinchiná. There, a thousand people lost their lives, and 200 houses and three bridges were destroyed. The first lahar reached Armero about 11:30 p.m., with more lahars following; there, they killed more than 20,000 of the town’s 29,000 residents and left another 5,000 injured.

The lahars destroyed everything in their paths: roads, bridges, farm fields, aqueducts and telephone lines. They wiped out 50 schools, two hospitals and more than 5,000 homes. The region lost 60 percent of its livestock, 30 percent of grain and rice crops, and half a million bags of coffee. About 7,500 people were left homeless.

Lessons Learned

The lahars descended through the steep, narrow drainages and river canyons on Nevado del Ruiz at speeds reaching 50 kilometers per hour. Credit: U.S. Geological Survey.

Marso, who arrived a couple of days after the eruption with two other scientists, describes it as a frenetic and chaotic time. “There was a lot of ash and mud on the landscape,” he says. The U.S. military came to aid in search and rescue operations. “Once we got there, our primary focus was to quickly establish monitoring, because at that point, we didn’t really know what had happened — or what could happen,” Marso says. Even after the eruption, he says, some 90 percent of the ice was still at the summit. If more, or larger, eruptions were to occur, even more people — including those involved in search and rescue — would be endangered. “We spent quite a lot of time flying, putting instruments in the field.” Eventually, other scientists across disciplines showed up to study the volcano.

Volcano emergency management is not easy, Marso says. It takes communication and trust among scientists, local residents and government officials. “In the case of Ruiz, it almost worked perfectly,” says Marso, until it didn’t. In the aftermath, researchers realized that one of the biggest problems was that Armero and the towns nearest the volcano were without power so communication broke down; the scientists had no ability to alert the townspeople to evacuate. With two hours and 21 minutes between the eruption and the first lahar reaching Armero, the town could have been evacuated if communication systems had worked.

“A good partnership between science and civil authorities is essential to protecting people,” Marso says. The Ruiz eruption was a lesson for the world, and resulted in the formation of VDAP. Before Ruiz, a few scientists had been pushing to make a response team happen, but the question was how to fund it, Marso says. “Ruiz made it easier.” Now, VDAP maintains a response team and cache of equipment to respond quickly.

When Mount Pinatubo in the Philippines began to awaken in April 1991, VDAP responded. At the time, most officials thought that Pinatubo was not active and that an eruption would not be dangerous. However, by the third week of April, VDAP sent in a three-person team with monitoring gear. In collaboration with local scientists from the Philippine Institute of Volcanology and Seismology (PHIVOLCS), the team set up a network of seismometers and various instruments around Pinatubo to determine if an eruption was imminent. At the same time, scientists worked to understand the eruptive history of Pinatubo.

As activity increased, and an eruption became more likely, the teams developed response plans and hazard maps. When Pinatubo erupted on June 15, the surrounding area had already been evacuated. In total, about 300 people were killed, but 5,000 could have been. Pinatubo was the second-largest eruption of the 20th century (behind the 1912 eruption of Alaska’s Novarupta), but the combined PHIVOLCS-USGS team had forewarned emergency managers, who had moved most people out of harm’s way.

Colombia, in particular, did not want this kind of tragedy to repeat itself and made serious efforts to prevent it from happening again, Marso says. In 2007, Nevado del Huila — the highest volcano in Colombia — reactivated. VDAP assisted the local INGEOMINAS volcano observatory (now called the Servicio Geológico Colombiano) to improve the monitoring network. In 2008, when the volcano erupted at 9:45 p.m., more than 4,000 people were evacuated from the nearby town of Belalcázar. When a lahar swept through the town less than an hour later, no one was killed. “It was an amazing success, and a testament to the work done in Colombia, with assistance from the U.S., VDAP and other organizations, to see that crises do not become disasters,” Marso says. In 2008, “the Colombians got it absolutely right.”

Nevado del Ruiz hasn’t produced a catastrophic eruption since 1985, though it remains active. Early in 2016, a magnitude-2.9 earthquake occurred under the volcano. And, throughout this year, Ruiz has ejected occasional ash emissions, some reaching up to 1 kilometer high. Today, Marso says, “it’s probably one of the best-monitored volcanoes in the world.”

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How the Armero Tragedy Changed Volcanology in Colombia

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On 13 November 1985, the Nevado del Ruiz volcano erupted, killing more than 25,000 people in Armero—a town of 30,000 inhabitants—making it the worst natural disaster in the history of Colombia.

Marta Lucía Calvache Velasco , the technical director of the Colombian Geological Service (SGC), was studying the volcano 1 month before the eruption. She and her colleagues had submitted a report to the Colombian congress describing the geological history of the site and warning of the likelihood of an eruption within the next months or years.

The warnings were mostly ignored. The documentary El valle sin sombras (The valley without shadows) by Colombian filmmaker Rubén Mendoza compiled the experiences of some survivors. Resident Gabrielina Ferruccio says in the film that when ash started falling on Armero on the eve of the eruption, she went to church to ask for advice; the priest told her to “enjoy this beautiful show, it will never be seen again.” Edilma Loiza remembers how at 6 p.m., “a fire truck went through town telling everybody to stay at home, to not leave home or panic.” The catastrophic lahars (avalanches of volcanically induced landslides and debris flows) occurred 5 hours later.

The second volume of the book Forecasting and Planning for Volcanic Hazards, Risks, and Disasters (2020) includes a chapter written by a group of Colombian geologists led by Calvache. They describe how geologists in the country have worked to avoid future disasters by improving monitoring, creating a legal framework, and raising awareness in at-risk populations. The text clarifies how Colombian volcanologists realized that studying natural phenomena was irrelevant if they could not share their knowledge in a way that policymakers and the public understood the urgency to avoid predictable tragedies.

Monitoring and Studying Volcanic Hazards

“The fact that there is a volcanic eruption should not be a synonym for disaster.”

Colombian volcanology grew rapidly and exponentially thanks to international aid that arrived after the disaster and helped establish a network of observatories. Today, there are 600 stations that monitor and investigate 23 active volcanoes . Additionally, 14 hazard maps have been produced for local authorities to use. “The fact that there is a volcanic eruption should not be a synonym of disaster,” said Calvache. Policymakers and scientists learned they could protect the nearby communities as long as they understood what was happening geologically.

In June 1989, the Nevado del Ruiz had an eruption similar to the one that destroyed Armero. As soon as one of the new monitoring stations detected an increase in seismic activity, the SGC started to produce daily updates on the status of the volcano. On 30 August, the SGC told the local community that an eruption was imminent and evacuations were necessary.

Just 4 years after the Armero tragedy, when the Nevado del Ruiz erupted again, there was no human loss.

Legal Framework

“In 1985, Colombia didn’t even have an institution in charge of volcanoes,” remembered volcanologist Diego Mauricio Gómez Martínez of the SGC. Geologists advocated for the passage of decree 919 of 1989 , which created the first legal and institutional framework for risk management in the country. The agency it created, Ingeominas, was put in charge of assessing and preventing volcano risk; in 2012 the agency changed its name to the SGC.

The legal framework has brought new and unforeseen problems, as well as ways to address existing ones.

Lucio Figuero, an Indigenous leader who has lived more than 60 years near the Galeras volcano (named Urkunima by locals, meaning “mountain of fire” in the Quillasinga language), argues that the risk management strategy has been negative for his community, for example. When the volcano reactivated in 2004, the locality of Mapachico, where Figuero lives, was designated a risk zone. With the new designation, “all possibilities of construction or investment stopped, condemning us to poverty.…The price of land devalued so much that if we sell it, we won’t have enough money to move anywhere else,” said Figuero.

Several families from the region brought a lawsuit demanding to be relocated outside the risk area of Galeras, which has erupted 25 times in the past 30 years. After their request was denied by several regional courts, the Colombian Constitutional Court ruled in their favor, arguing that resettlement was necessary because of “the fundamental rights to life and dignified housing.”

According to Figuero, new studies are being conducted to determine a new hazard map for the region—almost 10 years after the Constitutional Court ruling. He hopes that when the new hazard map is completed, his community will be able to stay in their territory and “learn to live with the volcan ,” although acknowledging there is a possibility they will have to be relocated. If that happens, he hopes the government will be able to provide some economic support.

Raising Awareness in At-Risk Populations

Monitoring and the legal framework are useful tools to prevent disasters. However, Calvache believes that community awareness of volcanic phenomena will ensure that if an eruption occurs, there will be no disaster. The SGC has partnered with local universities and schools to produce videos, posters, radio spots, and an online teaching module . “We have to do science that can be shared,” said Calvache.

Gomez believes that for the awareness to be effective, “communities need to be able to appropriate scientific knowledge.” This belief is the reason Gómez organized the first youth conference in Pasto after a visit to Japan in 2011, where he was inspired by the way risk prevention focused on the experiences of youth living in volcanic regions. He organized an event in which more than 150 children from all over Colombia shared their stories with peers, learned about volcanoes, and studied risk management.

The goal of such projects is to allow local communities to share their experiences and promote volcanic risk management for new generations in Colombia.

—Santiago Flórez ( @rflorezsantiago ), Science Writer, with additional reporting by Camilo Garzón ( @CamiloAGarzonC ), Science Writer

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Citation:  Flórez, S., and  C. Garzón (2021), How the Armero tragedy changed volcanology in Colombia,  Eos, 102, https://doi.org/10.1029/2021EO210628 . Published on 30 November 2021.

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November 13, 2011

November 13, 1985: The Nevado del Ruiz Lahars

By David Bressan

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American

The eruption started at 15:00 o'clock local time November 13, 1985 with smaller explosions in the crater. Ash was carried by the wind in north-eastern direction, however only minor ash fall occurred in the city of Armero (Colombia) , located 48 kilometers east of the " Cumanday " - the smoking nose, as the Indians used to call the volcano.

In the evening the intensity of the eruption increased, however it was still considered only a medium sized event for the Nevado del Ruiz. At 23:00 most of the 25.000 inhabitants of Armero were sleeping, despite some preoccupation for the sounds coming from the distant mountain, then suddenly - as an eyewitness describes - " the world screamed. "

The underground was trembling and a terrible roar followed. A mixture of water and debris overwhelmed the entire city. In 20 to 30 minutes three or four lahars (mudflows of volcanic material) occurred. Some survivors later reported that the first waves were formed by cold mud, followed by waves of hot mud. Nearly 22.000 people were killed by these mudflows that coming from the summit of the volcano followed the river valley of Lagunillas until reaching Armero.

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Video 1. Video produced by the World Health Organization to document the aftermath and rescue operations at Armero (the video shows victims and injured people - viewers discretion is advised).

The volcanic nature of the Nevado del Ruiz (5.389m) was already known in ancient times as the indigenous name reveals. The volcano erupted in historic times in the years 1595 and 1845; and already during this last eruption a mudflow killed 1.000 people in the Lagunillas valley.

Before 1985 the presence of vapour on the mountain summit was noted and a small glacial lake filled the bottom of the crater. In November 1984 an intense earthquake activity started, probably marking the slow rise of magma inside the volcano. In the last year, between December 1984 and September 1985, the volcanic activity steadily increased. The relatively small eruption from November 1985 melted partially the glaciers covering the Nevado del Ruiz (estimated 10% of the ice-area), forming the lahars that had such disastrous effects in the valleys surrounding the volcano.

After the catastrophe an intense debate about responsibility began, the compiled hazard map (one of the first in Colombia) of the entire area got widely ignored and misinterpreted, as were the signals of activity by the volcano. The authorities were informed previously that Armero was located on the deposits of the lahar of 1845 and a similar disaster could occur again even by minor eruption. After the disaster the government of Colombia created a special program to prevent such incidents in the future.

Bibliography:

DECKER, R. & DECKER, B. (1991): Mountains of Fire: The Nature of Volcanoes. Cambridge University Press. Cambridge: 243

The Management of Volcano Emergencies: Nevado del Ruiz

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This chapter analyzes the circumstances and events that contributed to the loss of 23 000 lives in the 1985 Nevado del Ruiz catastrophe, providing useful guidelines for the management of future volcano emergencies. The presentation is organized into two principal sections. The first is a condensed chronicle of events and actions taken from November 1984 through to November 1985 that provides the background for the crucial events of November 13. In the second section, factors are evaluated that influenced the catastrophic outcome, and lessons are identified to avoid similar future occurrences.

In hindsight, the government on the whole acted sluggishly, although with vigor after September; but it was not willing to bear the economic or political costs of early evacuation or a false alarm. Scientific studies foresaw the hazards — including the recognition that several towns were in the “wrong place”, vulnerable to lahars generated by eruption-induced snowmelt — but were insufficiently precise to prompt reliable warning of the crucial event before the last possible minute. Catastrophe was therefore the calculated risk, and this combination — the limitations of prediction/ detection, the underadvised and inadequately prepared local authorities, the unprepared populace, the refusal to accept a possible false alarm, and the lack of will to act on the uncertain information available — provided its immediate and most obvious causes. The crucial event occurred just two days before the Armero emergency-management plan was to be critically examined and improved. The numeroes misjudgments which delayed progress of emergency management over the previous year — especially the lack of a timely hazard map — contributed significantly to the tragic outcome. Thus, the catastrophe was not caused by technological ineffectiveness or defectiveness, nor by an overwhelming eruption or an improbable run of bad luck, but rather by cumulative human error.

The main lessons are that hazard assessments and maps should be prepared well in advance of volcanic crises, the most vulnerable communities should be identified and reliable mitigation measures (including thorough public education and a tested warning system) should be undertaken at a very early stage, and emergency management must confront in advance the issues of risk communication, uncertainty, and false alarms so that decision making is not delayed and rapid public response may occur during times of crisis.

“One learns more from defeat than from victory.” — Samuel Eliot Morison (1963, p. 187)

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Acosta J (1846) Relation de l’éruption boueuse sortie du volcan de Ruiz et de la catastrophe de Lagunilla dans la République de Nouvelle Grenade. CR Acad Sci 22: 709–710

Google Scholar  

Acosta J (1850) Sur les montagnes de Ruiz et de Tolima (Nouvelle Granada) et les éruptions boueuses de la Magdalena (Lettres à M. Elie de Beaumont). Bull Soc Geol Fr Ser II, 9: 489–496

Banks NG (1986) Hazard mitigation and rapid response to crises with mobile volcanic observatories (abstr.). EOS Trans Am Geophys Union 67 (16): 398

Banks NG, Van der Laat, R, Carvajal C, Serano, T (1986) Deformation monitoring at Nevado del Ruiz, Colombia (Abstr.). EOS Trans Am Geophys Union 67(16): 403

Banks NG, Carvajal C, Mora H, Tryggvason E (1990) Deformation monitoring at Nevado del Ruiz, Colombia October 1985-March 1988. In: Williams SN (ed) Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 41: 269–296

Barberi F, Martini M, Rosi M (1985) Informe de la misión tecnica para la evaluacion del riesgo volcánico del Nevado del Ruiz-Cordillera Central-Colombia. Manizales 22 Octubre 1985. Ministero degli Affari Esteri-Italia-Dipartimento Cooperazione per lo Sviluppo, Roma 18 pp

Barberi F, Martini M, Rosi M (1990) Nevado del Ruiz volcano (Colombia): pre-eruption observations and the November 13, 1985 catastrophic event. In: Williams SN (ed), Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 41: 1–12

Calvache ML (1986) The eruption of the Nevado del Ruiz volcano, Colombia (abst.). EOS Trans Am Geophys Union 67 (16): 405

Calvache ML (1990) Pyroclastic deposits of the November 13, 1985 eruption of Nevado del Ruiz, Colombia. In: Williams SN (ed), Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 41: 67–78

Calvache ML, Duque G, Garcia N, Salazar JE, Salazar B (1985) Memorias del Seminario Sobre Riesgo Voleánico del Ruiz: Nat Univ Manizales Rev Vias y Transport 12(53): 114 pp

Cepeda H, Michael J, Murcia A, Parra E, Salinas R, Vergara H (1985a) Mapa Preliminar de Riesgos Volcánicos Potenciales del Volcan Nevado del Ruiz. Esc. 1:50 000. Memoria Ex-plicativa. INGEOMINAS Medellin Oct 7, 1985, 22 pp

Cepeda H, Michael J, Murcia A, Parra E, Salinas R, Vergara H (1985b) Mapa de Riesgos Volcanicos Potenciales del Nevado del Ruiz. Exc. 1:100000. Memoria Explicativa. INGEOMINAS Medellin Nov 12, 1985, 28 pp

Cepeda H, Michael J, Murcia A, Parra E, Salinas R, Vergara H (1986) Volcano risk potential maps of Nevado del Ruiz, Volcano, Colombia (abstr.) EOS Trans Am Geophys Union 67 (16): 407

CHEC (Centrol Hidro-Eléctrica de Caldas) (1983) Investigación Geotérmica. Macizo Voleánico del Ruiz, Fase II Etapa A Vol. I-X. Min Energiá y Minas, Bogotá (in Spanish)

Chester D (1993) Volcanoes and Society. Edward Arnold, London, 351 pp

Cuéllar J, Solano A (1985) Informe Preliminar de las actividades desarrolladas, INGEOMINAS, Bogotá, October 1985, 19 pp

Decker RW (1986) Ruiz Volcano, Colombia: trip report, February-March 1986. US Geol Surv, Menlo Park, 45 pp (unpublished)

Decker RW, Decker B (1981) Volcanoes. Freeman, San Francisco, 244 pp

DeMarchi B (1993) Effective communication between the scientific community and the media. In: Nemec J, Nigg JM, Siccardi F (eds) Prediction and Perception of Natural Hazards. Kluwer, Dordrecht, pp 183–191

Dombrowsky WR (1993) The social dimensions of warning and the transition from folk wisdom to laymanship. In: Nemec J, Nigg JM, Siccardi F (eds) Prediction and Perception of Natural Hazards. Kluwer, Dordrecht, pp 23–28

Dymon UJ, Winter NL (1993) Evacuation mapping: the utility of guidelines. Disasters 17(1): 12–24

Article   Google Scholar  

Espinosa A (1986) Notas sobre la Acitividad Histórica del Volcán Nevado del Ruiz. INGEOMINAS, Cali, 17 pp

Fiske RS (1984) Volcanologists, journalists, and the concerned local public: A tale of two crises in the eastern Caribbean. In: Explosive Volcanism: Inception, Evolution, and Hazards. Geophys Study Committee, National Research Council, National Academy Press, Washington, pp 170–176

Francis P (1993) Volcanoes. Oxford University Press, Oxford

Giesecke A, Anzola P, Fernàndez B., Gonzàlez-Ferrán O, Hall M, Podestá B, Rodriguez A, Sarria A (1990) Riesgo Volcánico. Evaluation y Mitigación en America Latina. (Aspectos sociales, institucionales y cientificos. Centro Regional de Sismologia para América del sur-CERESIS [Apartado Postal 14–0363], Lima, Perú, 288 pp

Gil CF, Myer HJ, Chouet B, and Harlow D (1987) Observations of long-period events and tremors at Nevado del Ruiz Volcano 1985–1986. Hawaii Symp on How Volcanoes Work. Abstr Vol, Hawaiian Volcano Observatory, Hilo, Hawaii, Jan 19–25, p. 90

Gueri M, Perez LJ (1986) Medical aspects of the “El Ruiz” avalanche disaster, Colombia. Disasters 10: 150–157

Hall ML (1985) Activities and conclusions of visit by Dr. M. Hall to Volcán Nevado del Ruiz, Colombia. Instituto Geofisco, Escuela Politécnica Nacional, Quito, 4 pp. (Mission report; English and Spanish versions with subtle differences)

Hall ML (1990) Chronology of the principal events before the eruption of November 13, 1985. In: Williams SN (ed) Nevado del Ruiz, Volcano, Colombia. J. Volcanol Geotherm Res 41: 101–115

Hall ML (1992) The 1985 Nevado del Ruiz eruption: scientific, social, and governmental responses and interaction before the event. In: McCall GJH, Laming DJC, Scott SC, Geohazards:natural and man-made. Chapman and Hall, London, pp 43–52

Harlow DH, Munoz C, Cuellar J (1986) Seismic activity preceding the 13 November 1985 eruption of Ruiz volcano, Colombia (Abstr) EOS Trans Am Geophys Union 67 (16): 403

Herd G (1982) Glacial and volcanic geology of the Ruiz-Tolima complex, Cordillera Central, Colombia. Publ Geol Espec INGEOMINAS No 8, Bogotá, 48 pp

Herd G, Comité de Estudios Vulcanológicos (1986) The 1985 volcano disaster. EOS Trans Am Geophys Union 67 (19): 457–460

Hermelin M, Velásquez A, Bustamente M (1986) Aspectos históricos de eruptiones en el Volcan Nevado del Ruiz. Bol Vias 13 (56): 37 pp

Hess J (1987) Report from Washington. GSA news and information. Geol Soc Am, Boulder, Nov, p 248

Janda RJ, Banks NG, Pierson TC, Calvache ML, Thouret JC (1986) Interaction between ice and pyroclastic sediments erupted during the 13 November 1985 eruption of Nevado del Ruiz, Colombia (Abstr) EOS Trans Am Geophys Union 67 (16): 406

Katsui Y, Takahashi T, Egashira S, Kawachi S, Watanabe H (1986) The 1985 eruption of Nevado del Ruiz volcano, Colombia, and associated mudflow disaster. Report of Natural Disaster Scientific Research, no B-60–7 (Japan Ministry of Education): 61–91

Khan MI (1991) The impact of local elites on disater preparedness planning: the location of flood shelters in northern Bangladesh. Disasters 15(4): 340–354

Lima BR, Santa Cruz H, Lozzano J, Luna J (1988) Planning for health/mental health integration in emergencies. In: Lystad M, (ed), Mental health responses to mass emergencies. Brunner and Mazel, New York, pp 371–393

Martinelli B (1990) Analysis of seismic patterns observed at Nevado del Ruiz volcano, Colombia, during August-September 1985. In: Williams SN (ed) Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 41: 297–314

Martinelli B (1991) Understanding triggering mechanisms of volcanoes for hazard evaluation. Episodes 14(1): 19–25

Medina JP (1986) The organization of the group to monitor volcano Nevado del Ruiz in Colombia (abstr.) EOS Trans Am Geophys Union 67 (16): 403

Mileti DS (1993) Communicating public earthquake risk information. In: Nemec J, Nigg JM, Siccardi F (eds) Prediction and perception of natural hazards. Kluwer, Dordrecht, pp. 144 – 152

Mileti DS, Fitzpatrick C (1991) Communication of public risk: its theory and its application. Sociological Practice Rev 2(1): 20–28

Mileti DS, Sorenson JH (1988) Planning and implementing warning systems. In: Lystad, M (ed), Mental health response to mass emergencies. Brunner-Mazel, New York, pp 321–345

Mileti DS, Bolton PA, Fernandez G, Updike RG (1986) Recommendations for improving the existing warning system for an impending eruption of the Nevado del Ruiz volcano, Colombia, S.A.: an advance report. Committee on Natural Disasters, National Academy Press, Washington, 10 pp

Mileti DS, Bolton PA, Fernandez G, Updike RG (1991) The eruption of Nevado del Ruiz Volcano, Colombia, South America. Natural Disasters Studies, vol 4, National Academy Press, Washington, 109 pp (based on information available in 1986)

Miller CD, Mullineaux DR, Hall ML (1978) Reconnaissance map of potential volcanic hazards from Cotopaxi Volcano, Ecuador. Scale 1:100 000. US Geol Surv Misc Invest, Reston, Map I-1072

Miller CD, Ewert JW, Lockhart AB (1993) The USGS/USAID volcano disaster assistance program: the next five years. US Geol Surv Open File Rep 93–379, Reston, 7 pp

Mojica J, Colmenares F, Villarroel C, Macia C, Moreno M (1986) Characteristicas del flujo de lodo ocurrido el 13 de Noviembre de 1985 en el valle de Armero (Tolima, Colombia): Historia y comentarios de los flujos de 1595 y 1845. Geol Colomb 14: 107–140

Morchio R (1993) The effect of the uncertainties in natural hazard prediction in the user communities. In: Nemec J, Nigg JM, Siccardi F (eds.) Prediction and perception of natural hazards. Kluwer, Dordrecht, pp 39–47

Morison SE (1963) The two-ocean war. A short history of the United States Navy in the Second World War. Atlantic Monthly Press. Little, Brown Boston, 611 pp

Munoz F, Meyer H -J (1987) Seismic activity preceding the 13 November 1985 eruption at Nevado del Ruiz. Hawaii Symp on How volcanoes work. Abstr vol Hawaiian Volcano Observatory, Hilo, Hawaii, Jan 19–25

Munoz F, Meyer H-J, Harlow D (1987) Seismic activity preceding the 13 November 1985 eruption of Ruiz volcano, Colombia. Hawaii Symp on How volcanoes work. Abstr Vol Hawaiian Volcano Observatory, Hilo, Hawaii, Jan 19–25: 185

Munoz CF, Nieto EA, Meyer HJ (1990) Analysis of swarms of high-frequency seismic events at Nevado del Ruiz volcano, Colombia (January 1986-August 1987). In: Williams, SN (ed) Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 41: 327–354

Naranjo JL, Sigurdsson H, Crey SN, Fritz W (1986) Eruption of the Nevado del Ruiz Volcano, Colombia, on 13 November 1985: tephra fall and lahars. Science 233, 4767:961–963

Nemec J, Nigg JM, Siccardi F (eds.) (1993) Prediction and perception of natural hazards. Kluwer, Dordrecht: 226 p

Nieto EAH, Brandsdottir B, Munoz CF (1990) Seismicity associated with the reactivation of Nevado del Ruiz, Colombia, July 1985-December 1986. In: Williams SN (ed), Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 41: 315–326

Parra E, Cepeda H (1990) Volcanic hazard maps of the Nevado del Ruiz volcano, Colombia. In: Williams SN (ed) Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 41: 117–128

Perry RW, Lindell M K, Green MR (1981) Evacuation planning in emergency management. Lexington Books, Lexington, MA

Petak WJ, Atkisson AA (1982) Natural hazard risk assessment and public policy. Springer, Berlin Heidelberg New York

Book   Google Scholar  

Peterson DW (1986) Volcanoes: tectonic setting and impact on society. In: Active tectonics. National Academy Press, Washington, pp 231–245

Peterson DW (1988) Volcano hazards and public response. J Geophys Res 93: 4161–70

Peterson DW, Tilling RI (1993) Interactions between scientists, civil authorities and the public at hazardous volcanoes In: Kilburn CRJ, Luongo G (eds.) Active lavas. UCL Press, London, pp 339–365

Pierson TC, Janda RJ, Thouret J-C, Borrero CA (1990) Origin, flow behavior, and deposition of eruption-triggered lahars on 13 November 1986, Nevado del Ruiz, Colombia. In: Williams, SN (ed) Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 41: 17–66

Pinatubo Volcano Observatory Team (1991) Lessons from a major eruption: Mt. Pinatubo, Philippines. EOS Trans Am Geophys Union 72 (49): 545–555

Podesta B, Giesecke M (1990) El Nevado el Ruiz y el Riesgo Volcanico en America Latina. Centre Regional de Sismologia para América del sur-CERESIS, Lima, Peru, 50 pp. (Executive Summary of Giesecke et al. 1990)

Quarantelli EL (1993) The different worlds of science and mass communication: implications for information flow from the former to the latter. In: Nemec J, Nigg JM, Siccardi F (eds) Prediction and perception of natural Hazards. Kluwer, Dordrecht, pp 175–182

Rattien S (1990) The role of media in hazard mitigation disaster management. Disasters 14(1): 36 – 45

Rojas R, Correro CA (1986) Velocidad, descarga maxima y volumen del lahar del Rio Chinchiná, 13 Noviembre 1985. In: Proc Simposio Internacional sobre Neotectonica y Riesgos Volcanicos, Bogotá, Colombia, Diciembre 1–7, 1986

SEAN (1985) Ruiz volcano, Colombia: Smithsonian Institution. SEAN Bull 10 (11): 2–5

Sigurdsson H, Carey S, Palais JM, Devine J (1990) Pre-eruption compositional gradients and mixing of andesite and dacite magmas erupted from Nevado del Ruiz volcano, Colombia in 1985, In: Williams SN (ed), Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 341: 127–152

Simon P (1625) Noticias Historiales de las Conquistas de Tierra Firme en las Indias Occidentales. Casa Editorial de Medardo Rios, Bogotá, 376 pp (1892)

Singer E, Entreny P M (1993) Reporting on risk: how the mass media portray accidents, diseases, disasters and other hazards. Russell Sage Foundation, New York, 288 p

Smith PJ (1990) Redefining decision: implications for managing risk and uncertainty. Disasters 14(3): 230–240

Sorensen JH and Mileti, DS (1987) Public warning needs. US Geol Surv Open File Rep 87 – 269, 9–75

Thouret J-C, Murcia LA, Salinas R, Perignon NV, Cantagrel JM (1985) Cronoestratigrafia med-iante dataciones K-AR y C-14 de los volcanoes Compuestos del Complejo Ruiz-Tolima y aspectos volcanoestructurales de Nevado del Ruiz (Cordillera Central, Colombia). Mem VI Congr Latinoamericano del Geol, Bogotá, Tom 1: 385–454

Thouret J-C, Janda RJ, Pierson TC, Calvache ML, Cendrero A (1987) L’eruption du 13 Novembre 1985 au Nevado El Ruiz (Cordillere Centrale, Colombie); interactions entre le dynamisme eruptif, la fusion glaciaire et la genese d’ecoulements volcano-glaciaires. C R Acad Sci ser II 305: 505–509

Thouret J-C (1990) Effects of the November 13, 1985 eruption on the Snow Pack and ice cap of Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res 341: 177–202

Tilling RI (1989) Volcanic hazards and their mitigation: progress and problems. Rev Geophys 27 (2): 237–269

Tomblin J (1985a) Report of a mission from 25 Sept-2 Oct. 1985. UNDRO, Geneva, 9 October, 5 pp and 6 Annexes

Tomblin J (1985b) Ruiz — A sleeping giant awakes. UNDRO News Office of the United Nations Disaster Relief Coordinator, Geneva, Nov/Dec, 1985 7 pp

Tomblin J (1988) UNDRO’s role in responding to volcanic emergencies. UNDRO News Office of the United Nations Disaster Relief Coordinator, Geneva, March/April 1988, 7–10

UNDRO (1985) Volcano emergency management. Office of the United Nations Disaster Relief Coordinator, United Nations, New York, 86 pp

Van der Laat R (1985) Informe de la misión técnica para la implementación de estudios de deformación del Volcán Nevado del Ruiz, Colombia. Unpubl Informe del Observatorio Vulcanológico y Seismológico de Costa Rica,.Univ Nacional Heredia, 23 pp and 15 pp Anexo

Velasquez A, Hermelin M, Bustamente M (1986) Activated del Volcan Nevado del Ruiz en épocas historicas. Bol Vias 13 (59): 20 pp

Voight B (1986) Gravitational failure hazards, Nevado del Ruiz, Colombia-Misson from 30 January to 16 February 1986. Comité de Estudios Vulcanológicos, Manizales 20 pp.

Voight B (1988) Countdown to catastrophe. Earth Miner Sci 57(2): 17–30

Voight B (1990) The 1985 Nevado del Ruiz volcano catastrophe: anatomy and retrospection. J Volcanol Geotherm Res 44: 349–386

Voight B, Calvache ML, Ospina HO (1986) Is the Arenas crater at Nevado del Ruiz endangered by gravitational slope collapse? EOS Trans Am Geophys Union 67(16): 406

Voight B, Calvache ML, Ospina Herrera O (1987) High-altitude monitoring of rock mass stability near the summit of Volcano Nevado del Ruiz, Colombia. Proc 6th Cong Int Soc for Rock Mechanics p 275

Waitt RB, Jr, Pierson TC, McLeod NS, Janda RJ, Voight B, Holcomb RT (1983) Eruptiontriggered avalanche, flood, and lava at Mount St. Helens — effects of winter snowpack. Science 221(4618): 1394–1396

Williams SN (ed) (1990) Nevado del Ruiz Volcano, Colombia. J Volcanol Geotherm Res Spec Issue 1:41 (1–4): 1–379; 11:42 (1): 1–224

Wolf T (1878) Der Cotopaxi und seine letzte Eruption am 26 Juni 1877. N Jahrb Mineral Geol Paleontol, pp 113–167

Zollweg JE (1990) Seismicity following the 1985 eruption of Nevado del Ruiz, Colombia. In: Williams (ed) Nevado del Ruiz Volcano, Colombia. J. Volcanol. Geotherm Res 41: 355–368.

Zollweg JE, Harlow DH, White RA, Norris RD, Guendel F (1986) Post-eruption seismicity at Nevado del Ruiz, Colombia: implications of the reservoir system and continued activity. EOS Trans Am Geophys Union 67(16): 406

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Voight, B. (1996). The Management of Volcano Emergencies: Nevado del Ruiz. In: Monitoring and Mitigation of Volcano Hazards. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-80087-0_22

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The Eruption of Nevado Del Ruiz Volcano Colombia, South America, November 13, 1985 (1991)

Chapter: 4 preeruption awareness and preparedness, preeruption awareness and preparedness, historical eruptions and experience.

Experience with disasters has long been recognized as an important factor that can influence what people—as individuals and in groups—perceive future risk to be, as well as what they do to mitigate and prepare for future events. Prior to the November 13, 1985 eruption of Nevado del Ruiz, however, recent history did not provide the people of Colombia with experiences to point out the dangers of the Ruiz volcano.

It has been estimated that some ten major eruptions of the Ruiz volcano have taken place during the past 10,000 years, occurring on an average interval of 160 to 400 years (Herd, 1986). The last major volcanic event at Ruiz was in 1595. In 1845, an earthquake, phreatic eruption (Herd, 1986), or avalanche (UNDRO, 1985) caused a giant mudflow that killed 1,000 people as it traveled 86 km down the Lagunillas River to the Magdalena River. This 1845 lahar traversed the current site of Armero (Acosta, 1850). Two significant earthquakes occurred in 1826 and 1827. Finally, in 1916, a more minor event resulted in ashfall in the city of Manizales in Caldas State. The volcano has remained virtually dormant since then.

The relatively minor eruptive events at Ruiz since 1595 and the lack of events of sufficient magnitude (from a social perspective) to illustrate lahar risk since 1845 did little to convince those at risk that volcanoes are a major and significant Colombian natural hazard.

This is illustrated by a 1985 Colombian Civil Defense publication, What to do in Case of Disaster. The booklet, which was prepared for public distribution, describes about a dozen hazards along with suggested protective public actions; volcanic hazard is not mentioned.

Pointing up this oversight is in no way an attempt to single out the

people of Colombia for criticism. Few are able to recognize a hazard that, for all practical purposes, has not manifested itself for some 140 years. This lack of local experience with volcanic hazards, and, thus, the virtual absence of volcano risk perception among the Ruiz area residents, was likely a major obstacle faced by those scientists and officials who recognized the danger, engaged in preparedness for an emergency, and sought to ready the public to respond.

INITIAL THREAT DETECTION

The ability to predict the precise time and magnitude of a natural disaster depends on two factors: the current state of scientific knowledge about a particular disaster and local observations of precursor activities to the disaster. The earliest perception of threat associated with Ruiz was in December 1984. A landslide formed a dangerous natural dam. At about the same time, mountain climbers began to feel and report earthquakes and gas plumes. These activities persisted, and in February 1985 several geologists from INGEOMINAS (the National Institute of Geology and Mines) conducted a site visit. In March 1985, the Colombian Civil Defense (Defensa Civil de Colombia) and INGEOMINAS requested that the United Nations Disaster Relief Organization (UNDRO) send a scientist to study the volcano.

John Tomblin of UNDRO inspected Ruiz in March 1985. Tomblin concluded that the observed earthquakes and gas plumes could be indicative of an eruption and he recommended that INGEOMINAS install seismographs to monitor the volcano. In addition, he suggested that a risk map be prepared to illustrate the potential hazard associated with an eruption of the volcano. Further, he recommended that the Defensa Civil de Colombia draft an emergency plan to facilitate public warnings and evacuation for high-risk areas.

Thus, INGEOMINAS began a project to monitor and define the volcanic risk in the Ruiz vicinity. In May, UNDRO funded a reevaluation of Ruiz by Minard Hall of the Instituto Geofísico of the Escuela Politécnica Nacional of Ecuador. In May 1985, the U.S. Geological Survey initiated a cooperative effort with UNDRO to provide scientific equipment to monitor Ruiz. First steps began in July 1985 when four portable seismographs were installed on the mountain. At about the same time, the Ruiz Volcanic Risk Committee was formed. Its charge was to begin volcanic monitoring, local emergency planning, and public education about volcanic risk.

In August, the installed seismographs recorded 5-20 earthquakes each day (Herd, 1986). INGEOMINAS pointed out that, on average, such earthquakes have, on a global basis, accompanied large volcanic eruptions about 25 percent of the time throughout recorded history. A minor eruption of steam, ash, and rock occurred on September 11, 1985; this event captured government attention although no one was injured. Surveillance of the volcano contin-

ued, and by October more seismographs and tiltmeters were installed on Ruiz. On November 12, 1985, the day prior to the major eruption of Ruiz, geologists who climbed to the summit to collect gas samples observed no clear signs of an imminent explosion.

EFFORTS TO INCREASE AWARENESS

A variety of efforts were undertaken to increase awareness of the risk presented by Nevado del Ruiz subsequent to the scientific discovery of an impending eruption and prior to the November 13, 1985 event. These efforts involved many Colombian and other organizations.

Instituto Nacional de Investigaciones Geológico-Mineras (INGEOMINAS)

In August 1985, INGEOMINAS published the first of a variety of reports designed to organize for or further the understanding of volcanic risk in response to the Ruiz threat. The first of these reports, Riesgos Sísmicos y Volcánicos Del Parque Natural De Los Nevados (Seismic and Volcanic Risks of Los Nevados Natural Park), was an effort to report on recommended research and monitoring on six Colombian volcanoes and the areas around them. The research agenda proposed recognized the volcanic risk in Colombia, particularly in volcanic regions where people lived close by. The report requested a budget to perform the recommended studies and recognized the inevitable involvement of international scientists in the study of Ruiz.

The proposed project was designed to be undertaken in stages, and it recognized the need for additional funds and international assistance. It also pointed to the need to involve organizations at all levels of Colombian government—including local governments—to define risk and hazard. The preliminary request sought funding to prepare a volcanic risk map for Ruiz; it was recognized that such a map would be needed to help make good hazard preparedness decisions.

A preliminary version of the risk map was completed on October 7, 1985, and it was accompanied by an explanatory report entitled Mapa Preliminar De Riesgos Volcánicos Potenciales Del Nevado Del Ruiz (Preliminary Map of Potential Volcanic Risks Associated with Nevado del Ruiz). An additional report accompanied the preparation of the risk map. This report, entitled Informe Preliminar De Las Actividades Desarrolladas Período Julio 20-Octubre 7 de 1985, explained that Ruiz was in a stage of activity but that it could not be precisely predicted when an eruption would occur. Continued volcanic activity was reported along with minor ashfall, de-icing of the mountain top, small mudflows, and increased volcanic crater size. The

report stated that there was a 100 percent chance of catastrophic lahars when Ruiz erupted.

INGEOMINAS held a meeting in mid-October to introduce the October 7, 1985 risk map to other national agencies. The map was revised in November 1985 in a report issued on the 10th of that month, Mapa De Riesgos Volcánicos Potenciales Del Volcánicos Nevado Del Ruiz. This revised map and report were based on additional scientific data, but both maps foretold the total inundation of Armero in the event of an eruption. Finally, on November 10, 1985, INGEOMINAS issued a final preeruption report, Informe De Las Actividades Desarrolladas (Período Octubre 8-Noviembre 10, 1985) (see Figure 4.1 ) in which risk estimates were the most precise. Risk maps reached local communities and were posted in local civil defense offices.

It was difficult for nongeologists (Congress and local officials) to accept the risk imposed by Nevado del Ruiz as revealed in the sequence of reports and maps issued by INGEOMINAS. For example, the Colombian Congress

FIGURE 4.1 Risk map released on November 10, 1985, depicting risks associated with a future eruption of Nevado del Ruiz (original map in color).

Civil Defense

The Colombian Civil Defense responded to the risk foretold by INGEOMINAS as early as April 1985. In the period between April and October 1985, Colombian Civil Defense spent some 5.3 million pesos on equipment to support emergency preparedness. These resources were expended on emergency communication equipment, uniforms and boots, ambulance tires, gas masks, emergency food and rations, and other items, including body bags. This effort to support preparedness and disaster response was spread throughout the entire area, in all the communities at risk.

In September 1985, after hazard maps work was under way, the director of civil defense created a plan for emergency response to the risk and eruption of Nevado del Ruiz. The plan was based on an assessment of what still remained to be accomplished and was prepared in concert with the National Committee of Regional and Local Organizations, which was established to address the threat of an eruption of Ruiz. The plan consisted of planning elements and implementing procedures for the evacuation of risk areas.

Additionally, in September 1985, the Colombian Civil Defense began flights over the mountain and river valleys near Ruiz to collect risk information. It was also in September that Civil Defense and INGEOMINAS met with Parliament to explain the risk of an impending eruption of Nevado del Ruiz and to discuss the resources needed for preparedness and mitigation, as well as the training needed to accomplish this work.

October 1985 saw even more intense efforts on the part of Civil Defense to prepare for an eruption. Radio communications were augmented in quantity and quality with both fixed and mobile communication devices. This was done in the four states in which risk was present: Tolima (the state encompassing the city of Armero), Caldas, Risaralda, and Quindio. Representatives of these four states conferred with the Colombian Civil Defense at the national level to provide local input into the planning process and the preparedness plans themselves.

Civil Defense volunteers from these same four states went to the towns and villages at risk to alert local officials to the danger and to disseminate information about what to do in the event of a disaster. Volunteers knew of the general risk of an eruption, but they lacked detailed information on the true dangers posed by lahars. This effort also included an attempt to build

up public confidence to “minimize the chance of public panic if and when a disaster occurred.” Civil Defense volunteers talked directly to local residents in areas at risk, including people in cities, towns, and smaller settlements, and also to squatters living along riverbanks. These conversations were an attempt to inform people about (a) what Civil Defense is, (b) the current general risk of an eruption of Ruiz, (c) preparedness for the disaster, and (d) initial aid after impact. The study team was unable to determine how many people were reached through such activities.

The efforts of Civil Defense in October extended even further. A census of the population at risk was compiled along the Gualí, Recio, Lagunilla, Azufrado, and Chinchina rivers. This census was a detailed field count of permanent and transient inhabitants at risk. Civil Defense held conferences in the cities of Armero, Chinchina, and Honda to provide risk and preparedness information. Although the Colombian Congress had criticized both the Colombian Civil Defense and INGEOMINAS, claiming that their efforts to increase awareness might scare the public, the study team found no evidence of public fear resulting from the effort to inform those at risk.

City and Regional Authorities

The Tolima Regional Emergency Committee was comprised of representatives from a variety of organizations. These included the Governor’s Office, the Army’s Sixth Brigade, the Regional Health Services, Civil Defense, the Red Cross, INGEOMINAS, and others. The committee contacted officials in local towns and cities at risk to inform them of the need for emergency preparedness and to encourage the development of local evacuation plans. The risk, of course, varied from town to town, and the committee was able to initiate various kinds of preparedness activities in many locales. The regional committee met many times prior to the November 13 eruption, but its last two meetings were particularly noteworthy.

On October 29, 1985, the Tolima Emergency Committee met at the office of the Red Cross. The information presented was elaborate. The risk map prepared by INGEOMINAS was presented and reviewed along with probability estimates for different events, including a worst case scenario. The monitoring activity associated with the volcano was outlined and discussed. Census data of the population at risk were presented. Emergency communications were reviewed by the Red Cross, as was the availability of some 3,000 Red Cross volunteer workers for disaster response. Additionally, the assistance reserves of some 150 countries was discussed as part of the disaster relief available. The meeting obviously made available a range of risk, preparedness, and disaster response information to some dozen at-risk communities.

On November 13, the day of the eruption, the Regional Emergency Committee held a regularly scheduled meeting beginning at 5:00 p.m. The president of the Red Cross reported before the meeting officially began that there had been ashfall in the northern part of Tolima. The committee asked a representative of the police to send word to central command to alert all police stations to prepare for mudflows and floods along the shores of the rivers. The Red Cross alerted its field staff by radio and advised that they closely monitor low-lying areas. The director of INGEOMINAS advised those at the meeting what to do about ashfall; this advice was also disseminated over radio to the Red Cross and the police. The meeting was then called to order.

Three topics were discussed once the meeting was officially under way. First, the committee discussed with the police how best to communicate with outlying areas about the existing risk of ashfall and the potential risk of mud and flooding along riverbanks. Second, there was a detailed discussion of the agenda for a major committee meeting two days later on November 15, 1985. The agenda for this meeting was to be quite detailed and aimed at fine-tuning emergency response plans (for example, updating census data on river bank populations). Finally, the Red Cross reported that it had just received word by radio that the abnormal condition in northern Tolima had ended.

Public Information

In the weeks prior to the eruption, risk maps were distributed throughout the areas at risk in each city and town. Thousands of public information pamphlets were distributed (see Figure 4.2 ) and posted. For example, in September of 1985, public pamphlets were distributed in the State of Caldas that described mudflows and the magnitude of danger involved. In October, the Caldas emergency committee issued a new public brochure. It described the likely presence of environmental cues for the eruption (such as ashfall), as well as what people should do in response to the event. The public brochures for Tolima (the state containing Armero) discussed ashfall, volcanic gases, avalanches, inundation (especially along the larger rivers), explosions, and burning rock. The brochure also discussed what to do in an emergency: (a) in case of ashfall, remove the ash from your roof and cover your nose and mouth with a wet handkerchief; (b) in case of gases, use masks; (c) in case of avalanches or mudflows, evacuate zones near the shores of rivers and stay high in the hills.

It was reported that, in response to public information, a few people simply moved away from the rivers in October 1985, especially after seeing unusually dirty water in the rivers.

FIGURE 4.2 A sample of the public information flyer distributed in the weeks prior to the eruption to thousands of Ruiz area residents at risk. The flyer describes recommended emergency measures in the event of a volcanic eruption.

CONCLUSIONS

The efforts to share awareness of the magnitude of the risk imposed on Colombia by Nevado del Ruiz were extensive; hazard maps played a key role in the effort to educate local decision-makers. Risk was well recognized by INGEOMINAS, Civil Defense, the Red Cross, the Regional Emergency Committee, and others. This risk recognition was slower in coming for some groups than others. However, it was also reported to the study team that both the Colombian Congress and officials in Armero did not recognize the risk to be as great as did the other aforementioned groups. There was fear reported among members of Congress and on the part of local officials that citizens at risk would panic if they were told about the actual risk.

On November 13, 1985, catastrophic mudflows swept down the slopes of the erupting Nevado del Ruiz volcano, destroying structures in their paths. Various estimates of deaths ranged as high as 24,000 residents. Though the nature and extent of risk posed by the mudflows to local communities were well documented before the event and extensive efforts had been made to communicate this information to those at risk, the affected communities were caught largely unaware.

This volume analyzes the disaster's many aspects: the extent, constitution, and behavior of the mudflows; the nature of damage to structures; the status of the area's disaster warning system; and the extent of the area's disaster preparedness, emergency response actions, and disaster relief efforts—both at the time of the disaster and in the first few months following the event.

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Nevado del Ruiz - Volcanic eruption Case Study

• Rock landscapes and processes
• Created by: Ella8888
• Created on: 07-04-13 13:55
• Destructive plate margin (Subduction of Oceanic Nazca Plate beneath South American plate)
• Andes Mountain Range
• Had been dormant for 150 years
• Strato Volcano & Highest Columbian Volcano
• Nov 13th 1985
• Columbia, South America
• LEDC - All survivors had to be rescued by air but country didn't have a lot of air transport
• It happened at night - Rescuers were delayed and people were trapped in their homes
• Signs of eruption for a long time -People thought the volcano would never erupt
• Columbian government did not act quickly enough and evacuate the settlements at risk
• Columbia established warning and evacuation plan
• Outlined tropical planning areas
• Public education campaign
• Red cross  provided flyers
• Hazard map posters for towns at risk
• Evacuation route markers painted on buildings

Report Thu 9th October, 2014 @ 21:27

Its great but is there any way of viewing what is under some of the bubbles?

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Report on Nevado del Ruiz (Colombia) — 1 May-7 May 2024

Smithsonian Institution / US Geological Survey Weekly Volcanic Activity Report, 1 May-7 May 2024 Managing Editor: Sally Sennert.

Please cite this report as: Global Volcanism Program, 2024. Report on Nevado del Ruiz (Colombia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 1 May-7 May 2024. Smithsonian Institution and US Geological Survey.

Weekly Report (1 May-7 May 2024)

Nevado del Ruiz

4.892°n, 75.324°w; summit elev. 5279 m, all times are local (unless otherwise noted).

Geological Summary. Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers more than 200 km2. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the caldera of an older edifice. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. The prominent La Olleta pyroclastic cone located on the SW flank may also have been active in historical time. Steep headwalls of massive landslides cut the flanks. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption.

Source: Servicio Geológico Colombiano (SGC)