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The 1985 Nevado Del Ruiz Volcano Catastrophe: Anatomy and Retrospection

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The 1985 Nevado Del Ruiz Volcano Catastrophe: Anatomy and Retrospection Journal of Volcanology and Geothermal Research, 42 (1990) 151-188 151 Elsevier Science Publishers B.V., Amsterdam--Printed in the Netherlands The 1985 Nevado del Ruiz volcano catastrophe: anatomy and retrospection BARRY VOIGHT Penn State University, University Park, PA 16802, U.S.A. (Received December 1, 1989) Abstract Voight, B., 1990. The 1985 Nevado del Ruiz volcano catastrophe: anatomy and retrospection. In: S.N. Williams (Editor), Nevado del Ruiz Volcano, Colombia, II. J. Volcanol. Geotherm. Res., 42: 151-188. This paper seeks to analyze in an objective way the circumstances and events that contributed to the 1985 Nevado del Ruiz catastrophe, in order to provide useful guidelines for future emergencies. The paper is organized into two principal parts. In the first part, an Anatomy of the catastrophe is developed as a step-by-step chronicle of events and actions taken by individuals and organizations during the period November 1984 through November 1985. This chronicle provides the essential background for the crucial events of November 13. This year-long period is broken down further to emphasize essential chapters: the gradual awareness of the awakening of the volcano; a long period of institutional skepticism reflecting an absence of credibility; the closure of the credibility gap with the September 11 phreatic eruption, followed by an intensive effort to gird for the worst; and a detailed account of the day of reckoning. The second part of the paper, Retrospection, examines the numerous complicated factors that influenced the catastrophic outcome, and attempts to cull a few "lessons from Armero" in order to avoid similar occur- rences in the future. In a nutshell, the government on the whole acted responsibly but was not willing to bear the economic or political costs of early evacuation or a false alarm. Science accurately foresaw the hazards but was in- sufficiently precise to render reliable warning of the crucial event at the last possible minute. Catastrophe was therefore a calculated risk, and this combination - the limitations of predication/detection, the refusal to bear a false alarm and the lack of will to act on the uncertain information available - provided its immediate and most obvious causes. But because the crucial event occurred just two days before the Armero emergency-management plan was to be critically examined and improved, the numerous cir- cumstances which delayed progress of emergency management over the previous year also may be said to have contributed to the outcome. Thus the catastrophe was not caused by technological ineffectiveness or defectiveness, nor by an overwhelming eruption, or by an improbable run of bad luck, but rather by cumulative human error - by misjudgment, indecision and bureaucratic shortsightedness. Armero could have produces no victims, and therein dwells its immense tragedy. "We are all of us fellow passengers on the same planet and we are all of us equally responsible for the happiness and well-being of the world in which we happen to live..." (Van Loon's Geography). Introduction in 1846 in the Comptes Rendus of the Academy of Sciences, Paris, it captures the Colombian This report begins with Joaquin Acosta's ac- naturalist's observations of a flow of mud that count of tragedy on the Lagunillas; presented swept over the site of Armero in 1845: 0377-0273/90/$03.50 © 1990 Elsevier Science Publishers B.V. 152 B. VOIGHT "A great subterranean noise was heard in the vicinity regions..." of the Magdalena, from Ambalema to the village of Such ancient traditions encompass the last Mendez... This sudden noise was followed, within a major eruption at Ruiz, known through the considerably smaller area, by trembling of the ground. words of Pedro Sim6n, a Spanish priest who Then, descending along the Lagunillas from its sources in the Nevado del Ruiz, came an immense flood of thick came to the New Kingdom of Granada in 1604 mud which rapidly filled the bed of the river, covered or (Sim6n, 1625; cf. Espinosa, 1986; Vel~squez et swept away the trees and houses, burying men and al., 1986): animals• The entire population perished in the upper part and narrower parts of the Lagunillas valley. In the "It happened then, that on that day, month and year [12 lower part, several people were saved by fleeing March 1595]... there came from this volcano such a sideways to the heights; less happily, others were loud, hoarse, and extraordinary thunderclap, and after stranded on the summits of small hills from which it it three others not so strong, which were heard within was impossible to save them before they died... On ar- a radius of more than forty leagues.., the Spaniards riving at the plain with great impetus, the current of saw that the volcano hurled out a large amount of mud divided into two branches. The much larger one pumice, as big as ostrich eggs and from these down to followed the course of the Lagunillas toward the the size of dove's eggs, sparkling red like iron from the Magdalena; the other, after topping the high divide, forge, which resembled erratic stars. Some fell on them traversed the Santo Domingo valley.•, and hurled and on their horses, which disquieted them no little. itself into the Rio Sabandija, which was thus plugged by And on the side of this mountain which faced the east an immense dam. The danger seemed imminent for a •.. the waters of the Rio Guali, which wets the founda- flood of downstream lands. Happily, plentiful rain dur- tions of Mariquita, it and its companion which flows in ing the night produced enough water to begin clearing the south, called the Rio Lagunillas, both originating in a passage across this mass of broken trees, sands, the snow which melts from this mountain, ran so full of stones, and stinking mud, mixed with enormous blocks ash that it looked more like a thick soup of cinders than of ice which descended from the mountains in such like water. Both overflowed their channels leaving the abundance that after several days they had not melted land over which they flowed so devastated that for many entirely•.. The terrain covered by debris and mud is years afterward it produced nothing but small more than four leagues square; it presents the ap- weeds..." pearance of a desert or playa, on the surface of which loom up like many islands heaps of broken trees that resisted the impetus of the torrent. The depth of the Armero, which did not exist when Sim6n and mud layer varies greatly, and is much greater toward Acosta made their journeys, was built on the the upper part of the deposit where it often reaches 5 to 6 m. A realistic calculation indicates more than 300 site of these ancient mudflows. Therefore no million tons of muddy material from the flanks of precedent was established when on the evening Volc~in Ruiz..." of November 13, 1985, Nevado del Ruiz ignited to generate the worst volcanic mudflow Of this event: Acosta remarked in an 1850 let- disaster in historic time and the second worst ter to the French geologist Elie de Beaumont volcanic disaster of this century. Its death toll that all of the property which families had ac- ranks fourth in history, behind only Tambora cumulated in years of effort, the fruit of labor of in 1815 (92,000) and Krakatoa in 1883 (36,000), several generations, was lost in a mudflow both in Indonesia, and Mount Pel~e, Martini- which destroyed houses, harvests, flocks, and que, in 1902 (28,000) (UNDRO, 1986). rendered the land barren for a great many Shortly after 21:00 local time, a relatively years: "It is astonishing that none of the in- small magmatic eruption at the summit crater habitants of these villages, built on the of Volc~n Ruiz produced a series of pyroclastic solidified mud of old mass movements, has even flows and surges that turbulently scoured and suspected the origin of this vast terrain, which melted part of the summit's snow and ice cap, occupies an area at least equal to that of the and sent torrents of meltwater, slush, ice and province of the Rh6ne, although ancient tradi- pyroclastic debris in a plexus of sheet and chan- tions testify to the frequent mudflows in these neled cascades over the volcano flanks (Katsui THE NEVADO DEL RU1Z VOLCANO CATASTROPHE: ANATOMY AND RETROSPECTION 153 et al., 1986). In lower channels the flows percent of the region's livestock, thirty percent coalesced and entrained debris, vegetation and of its grain sorghum and rice crops, and half a ponded water to form lahars, the Javanese million bags of Coffee were lost. Lahars buried word used internationally to mean a mud of 3,400 hectares of the agricultured land, damag- debris flow of volcanic origin. ed or eradicated 50 schools and 2 hospitals, On the volcano's fertile western slope, over- destroyed 5,092 homes, 58 industrial plants bank flooding by lahars caused 1,100 fatalities and 343 commercial establishments, and at Chinchinh, Caldas Province, and destroyed damaged the National Coffee Research Center more than 200 houses and three bridges (E. in Chinchin£ About 7,700 were rendered Parra, P., written commun., 1986). Lahars homeless. Total damage exceeded a billion feeding the Rio Guali flowed northward and dollars (U.S. AID, written commun., 1986). then east, destroying homes near Mariquita. Thus "the majestic and silent Nevado del Ruiz, Shortly before midnight, in Tolima Province, transformed now to an active volcano, could not successive lahar waves obliterated Armero resist singing a hymn of destruction; and where (population 29,000), the prime regional there was life and hope of production, there is agricultural center.
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