Abstract
Cotopaxi volcano (Ecuador) is famous for production of large-scale laharsthrough melting of ice and snow on its summit glacier. The lahar hazard inthe northern valleys of the volcano is assessed through numerical simulationof a maximum expected event. Considerations of past activity suggest that anevent like that of the 1877 eruption is the maximum expected lahar event.Review of the historical records reveals that northerly flowing lahars initiallyfollowed the Rio Pita and Rio Salto; at ``La Caldera'', owing to a sharp bendin the channel, the lahar partly overflowed into Rio Santa Clara. The laharsalong Rio Pita and Rio Santa Clara were conveyed to the Los Chillos valley.The simulation, using an initial flow volume of 60 × 106 m3reproduces the maximum heights reached by the 1877 lahar along the northernvalley. The volume of lahar triggered by an eruption similar to that of 1877 isestimated to have a volume about 2/3 of that of 1877. This hypothesized reductionof volume is attributed to shrinkage of the summit glacier over the past century.However, dramatic population growth along valleys exposed to lahar hazard overthe past 100 years makes the present risk from lahars higher than in the past. Thesharp bend of ``La Caldera'' represents a crucial site controlling lahar propagation:should a lahar overflow into the Santa Clara valley the risk increases considerablydue to the much higher concentration of human settlements along the valley. Resultsof a lahar simulation in which the entire flow is artificially forced into Rio Pita suggestthat construction of a dyke at ``La Caldera'' to prevent overflow would substantiallyreduce the general risk in the area.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Almeida, E.: 1995, Flujos de lodo del volcan Cotopaxi, Revista Geografica n. 34, Instituto Geografico Militar, Quito.
Barberi, F., Caruso, P., Macedonio, G., Pareschi, M. T., and Rosi, M.: 1992, Reconstruction and numerical simulation of the lahar of the 1877 eruption of Ecuador, Acta Vulcanologica 2, 35–44.
Barberi, F., Coltelli, M., Frullani, A., Rosi, M., and Almeida, E.: 1995, Chronology and dispersal characteristic of recently (last 5000 years) erupted tephra of Cotopaxi (Ecuador): implications for long-term eruptive forecasting, J. Volcanol. Geother. Res. 69, 217–239.
Blong, R. J.: 1984, Volcanic Hazard. A Source Book on the Effect of Eruptions, Academic Press, Orlando, Florida.
Caruso, P. and Pareschi, M. T.: 1993, Estimation of lahar and lahar-runout flow hydrograph on natural beds, Envir. Geol. 22, 141–152.
Chen, C.: 1987, Comprehensive review of debris flow modeling concepts in Japan, Rev. Eng. Geol., Geol. Soc. Am. Rev. Eng. Geol. 7, 13–29.
Costa, J. E.: 1997, Hydraulic modeling for Lahar hazards at Cascades Volcanoes, Envir. Eng. Geosc. 3(1), 21–30.
Finnie, I.: 1972, Some observation on the erosion of ductile metals, Wear 19, 81–90.
Iverson, R. M.: 1997, The physics of debris flow, Rev. Geoph. 35, 245–296.
Iverson, R. M., LaHusen, R. G., Major, J. J., and Zimmerman, C. L.: 1994, Debris flows against obstacle and bends: dynamic and deposits, EOS Trans. Am. Geoph. Un. 75(44), 274.
Iverson, R. M., Schilling, S. P., and Vallance, J. W.: 1998, Objective delineation of lahar-inundation hazard zones, Geol. Soc. Am. Bull. 110(8), 972–984.
Jordan, E.: 1983, Die Vergletscherung des Cotopaxi Ecuador, Zeitsch Gletsh Glazial, 73–102.
Laenen, A. and Hansen, R. P.: 1988, Simulation of three lahars in the Mount St. Helens area, Washington, using a one dimensional, unsteady-state streamflow model, U.S. Geol Sur, Water-Resource Investigations Report 88–4004.
Lowe, D., Williams, S. N., Leigh, H., Connor, C. B., Gemmel, J. B., and Stoiber, R. E.: 1986, Lahars initiated by the 13 November 1985 eruption of Nevado del Ruiz, Colombia, Nature 324, 51–53.
McArthur, R. C., Hamilton, D. L., and Mason, R. C.: 1990, Numerical simulation of mudflows from the hypothetical failure of a debris blockage lake below Mt. St. Helens, WA. In: R. H. French (ed.), Hydraulics/Hydrology of Arid Land (H2AL), ASCE, New York, pp. 416–421.
Macedonio, G. and Pareschi, M. T.: 1992, Numerical simulation of some lahars fromMt. St. Helens', J. Volcanol. Geother. Res. 54, 65–80.
Major, J. J. and Pierson, T. C.: 1990, Rheological analysis of fine-grained natural debris-flow material. In: R. H. French (ed.). Hydraulics/Hydrology of Arid Land (H2AL), ASCE, New York, pp. 225–231.
Major, J. J. and Pierson, T. C. 1992, Debris flow rheology: experimental analyses of fine-grained slurries, Wat. Res. Res. 28(3), 841–857.
Montgomery, D. R., Panfil, M. S., and Hayes, S. K.: 1999, Channel-bed mobility response to extreme sediment loading at Mount Pinatubo, Geology 27(3), 271–274.
Naranjo, J. L., Sigurdsson, H., Carey, S. N., and Fritz, W.: 1986, Eruption of the Nevado del Ruiz Volcano, Colombia, On 13 November 1985: Thepra Fall and Lahars, Science 233, 961–963.
O'Brien, J. S. and Julien, P. Y.: 1988, Laboratory analyses of mudflow properties, ASCE J. Hydr. Eng. 114, 877–887.
O'Brien, J. S., Julien, P. Y., and Fullerton, W. T.: 1993, Mudflow simulation, ASCE J. Hydr. Eng. 119(2), 244–261.
Phillips, C. J. and Davies, T. R. H.: 1991, Determining rheological parameters of debris flow material, Geomorphology 4, 101-100.
Pierson, T. C.: 1985, Initiation and flow behaviour of the 1980 Pine Creek and Muddy River lahars, Mount St. Helens, Washington, Geol. Soc. Am. Bull. 96, 1056–1069.
Pierson, T. C.: 1995, Flow characteristics of large eruption-triggered debris flows at snow-clad volcanoes: constraints for debris-flow models, J. Volcanol. Geother. Res. 66, 283–294.
Pierson, T. C.: 1998, An empirical method for estimating travel times for wet volcanic mass flows, Bull. Volcanol. 60, 98–109.
Pierson, T. C., Janda, R. J., Thouret, J. C., and Borrero, C. A. 1990, Perturbation and melting of snow and ice by 13 November 1985 eruption of Nevado del Ruiz, Colombia and consequent mobilization, flow and depositions of lahars, J. Volcanol. Geother. Res. 41, 17–66.
Rodolfo, K. S. and Arguden, A. T.: 1991, Rain-lahar generation and sediment-delivery systems at Mayon volcano, Philippines. In: R. V. Fisher and G. A. Smith (eds), Sedimentation in Volcanic Setting, SEMP Special publication n. 45, pp. 71–87.
Scott, K. M.: 1988, Origin behavior, and sedimentologicy of lahars and lahar-runout flows in the Toutle-Cowlitz River System. U.S. Geol. Surv. Prof Pap. 1447–A.
Scott, K. M., Vallance, J.W., and Pringle, P. T.: 1995:, Sedimentology, behavior, and hazard of debris flows at Mount Rainer, Washington. U.S. Geol. Surv. Prof. Pap. 1547.
Sodiro, L.: 1877, Relacion sobre la erucion del Cotopaxi acaecida el dia 26 de junio de 1877, Imprenta Nacional, Quito, Ecuador.
Takahashi, T.: 1991, Debris flow. Balkema AA, Rotterdam, IAHR Monograph Series.
Thorpe, R. S., Francis, P. W., Hammil, M., and Backer, M. C. W. 1982, The Andes. In: R. S. Thorpe (ed.), Andesites, Chichester, John Wiley, pp. 187–205.
Tilling, R. I.: 1989, Introduction and overview. In: T. I. Tilling (ed.), Volcanic Hazard, American Geophysical Union Short Course in Geology, vol. 1, pp. 1–8.
Vallance, J. W. and Scott, K. M.: 1997, The Osceola mudflow from Mount Rainer: Sedimentology and hazard implications of a huge clay-rich debris flow, Geol. Soc. Am. Bull. 109, 143–163.
Vignaux, M. and Weir, G. J.: 1990, A general model for Mt. Ruapehu lahars, Bull. Volcanol. 52, 381–390.
Whymper, E.: 1880: Viajaes a traves de los Majestuoso Andes del Ecuador, Colleciòn Tierra Incognita 4, Ed. Abya-Yala, pp. 157–165.
Wolf, T.: 1878, Memoria sobre el Cotopaxi y su ultima eruption acaecida el 26 de junio de 1877, Imprenta del Comercio, Guayaquil, Ecuador, 64 pp.
Wolf, T.: 1904, Crònica de los fenòmenos volcànicos y terremotos en el Ecuador. Imprenta de la Universidad Central, Quito, Ecuador, 120 pp.
Yokoyama, I., Tilling, R. I., and Scarpa, R. 1984: International mobile early-warning system(s) for volcanic eruptions and related seismic activities. Paris: UNESCO FP/2106-82-01 (2286) 102 pp.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Aguilera, E., Pareschi, M.T., Rosi, M. et al. Risk from Lahars in the Northern Valleys of Cotopaxi Volcano (Ecuador). Natural Hazards 33, 161–189 (2004). https://doi.org/10.1023/B:NHAZ.0000037037.03155.23
Issue Date:
DOI: https://doi.org/10.1023/B:NHAZ.0000037037.03155.23