Eruption of the Nevado del Ruiz Volcano, Colombia, On 13 November 1985: Tephra Fall and Lahars

Naranjo, J. L.; Sigurdsson, Haraldur; Carey, Steven; Fritz, William J.

doi:10.1126/science.233.4767.961

Cited by 143 publications

(53 citation statements)

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“…Figure ]8 indicates that at 20 km in both hemispheres, aerosol extinction was increased most by Pinatubo and El Chichon, but the impact of Ruiz is significant. Although not shown, the Unified background reference extinction indicates an imprint of Ruiz aerosols as high as 29 km, which is consistent with estimates of the plume reaching 31 km [Naranjo et al, 1986], compared with 40 km for Mount Pinatubo [Holasek et al,1996] and 25 km for El Chichon [Hofmann and Rosen, 1984]. Figure 8 shows that the initial impact of Ruiz and El Chichon were felt most intensely in the high-latitude Northern Hemisphere, whereas the Pinatubo effect was stronger in the Southern Hemisphere.…”

Section: Background Reference Aerosol Extinction Climatologysupporting

confidence: 79%

A unified, long‐term, high‐latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology

2003

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A 22 year, high‐latitude, stratospheric aerosol and cloud database has been formed in a “unified” manner by combining the Stratospheric Aerosol Measurement (SAM) II, Stratospheric Aerosol and Gas Measurement (SAGE) II, Polar Ozone and Aerosol Measurement (POAM) II, and POAM III 1 μm aerosol extinction profiles. The database is “unified” in that it embodies similar aerosol extinction measurements, uses a single meteorological data set, and employs a single algorithm for calculating background extinction and cloud detection thresholds. Latitude is constrained to poleward of 45° in each hemisphere. The Unified cloud detection algorithm and database are designed for the straightforward addition of new data when other compatible data sets (e.g., SAGE III) become available. “Unified” cloud detection is similar to, but a refinement of, earlier attempts to identify polar stratospheric clouds (PSCs) with SAM II and POAM II data. The Unified algorithm is instrument‐independent and circumvents fundamental cloud detection pitfalls. The database contains over 73,000 (36,000) polar vortex‐region profiles in the Antarctic (Arctic) and over 21,000 (2000) PSC observations. An introductory climatology of Unified “background” extinction is presented. It is seen that volcanic effects dominate the evolution of outside‐vortex background extinctions, but perturbations apparently not related to volcanoes are seen as well. Interannual variations of background extinction inside the austral vortex are seen to be nearly decoupled from volcanic effects, while in the Arctic, inside‐vortex extinctions show a considerable volcanic influence. An analysis of long‐term PSC sighting is presented. Midwinter (July and January) PSC and clear‐sky measurements at 20 km, in a fixed temperature range, are used for computing PSC probability. The grand average PSC probability calculated this way is nearly identical between hemispheres. In the Antarctic the interannual PSC probability pattern is distinctly cyclic but is convoluted by volcanic perturbations in background aerosol. In the Arctic the PSC probability has much less temporal coherence than in the Antarctic but is similarly impacted by volcanic background increases. An explanation for the variation in PSC probabilities, in terms of interannual differences in denitrification, is discussed. Finally, a statistical analysis of tropopause height in relation to PSC formation is also presented. PSC observations are seen to be strongly associated with elevated tropopause heights, indicating that tropospheric, synoptic‐scale flow perturbations are the primary forcing mechanism for Arctic PSC formation, as evidenced in this long‐term satellite record.

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Section: Background Reference Aerosol Extinction Climatologysupporting

confidence: 79%

A unified, long‐term, high‐latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology

2003

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“…The principal eruption occurred on 13 November 1985 with no obvious precursors. Approximately 3.9 3 10 7 m 3 of tephra were erupted (Naranjo et al 1986), 660 000 t of SO 2 were released (Krueger et al 1990), and lahars were generated from melting of the icecap. The lahars flowed through the towns of Armero to the east and Chinchiná to the west, killing approximately 25 000 people.…”

Section: Nevado Del Ruiz Volcanomentioning

confidence: 99%

Mechanisms of degassing at Nevado del Ruiz volcano, Colombia

Stix

Layne

Williams

2003

JGS

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Nevado del Ruiz volcano is an andesite stratovolcano located in the northern Andes of Colombia. The volcano erupted on 11 September 1985, 13 November 1985, and 1 September 1989. The last two eruptions emitted juvenile solid material. This paper examines the volatile and light lithophile trace element contents of melt inclusions and matrix glasses from this juvenile material, and proposes a model for degassing within the volcano. Major element distributions in the glasses show two evolutionary trends, with subsidiary points that lie between the two trends. The data suggest the existence of two separate magmas, which have interacted, mingled, and mixed during their ascent and eruption. Water contents in melt inclusions, as determined by secondary ionization mass spectrometric analysis, are generally low, averaging between 1.6 and 3.3 wt.%. Halogen concentrations in the glasses range from 400 to 1200 ppm for fluorine and from 1100 to 1500 ppm for chlorine. Sulphur contents are low, not exceeding 500 ppm, with most glasses containing ,200 ppm. Lithium concentrations range from 20 to 40 ppm, beryllium from 1.5 to 2 ppm, and boron exhibits high variability from 30 to 100 ppm. The only significant difference between melt inclusions and matrix glasses is for water, with matrix glasses having significantly lower concentrations (,0.5 wt.%) than the melt inclusions. The generally elevated concentrations of boron in the magma may be a consequence of enrichment in the source region of the magma, i.e. by subduction of altered oceanic crust and/or sediments. Yet the large degree of boron heterogeneity in both melt inclusions and matrix glasses necessitates subsequent addition of boron at shallower depths as well, by the assimilation of crustal sedimentary rocks or by interaction with hydrothermal fluids. Evidence for pre-eruptive magma emplacement at shallow levels is provided by (1) anhydrous mineral assemblages of plagioclase and pyroxene, (2) high silica contents of glasses, and (3) low water contents in melt inclusions. When combined, these observations suggest a period of magma residence at shallow depths, probably ,3 km beneath the summit of the volcano. A multistage model of magma transport and degassing involves alternating periods of magma ascent and magma ponding. Initially, volatile-bearing magma ascends from depths of 9-15 km, driven by buoyancy. During decompression, the magma loses gas, particularly CO 2 and sulphur. The magma eventually ponds at its neutral buoyancy level. At this point, the gas-saturated magma cools and crystallizes, thereby liberating gas under isobaric conditions. As a result, CO 2 is depleted from the magma whereas H 2 O and SiO 2 are enriched. The H 2 O enrichment is caused by its increased solubility in the magma as CO 2 is degassed, whereas SiO 2 is enriched by fractional crystallization. The density of the magma decreases as the level of dissolved H 2 O increases, eventually causing the magma to become buoyant once more and to continue its ascent, either to erupt or to freeze a...

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“…The largest eruption during the studied period (1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999) was the phreato-magmatic eruption of 13 November 1985 with 3.8×10 7 m 3 of ejected material (Naranjo et al 1986). The eruption of 1 September 1989 was much smaller in size with 1.6×10 6 m 3 of ejected material (Mendez and Patiño 1993).…”

Section: Recent Activity Of Nevado Del Ruiz Volcanomentioning

confidence: 97%

A warning model based on temporal changes of coda Q for volcanic activity at Nevado Del Ruiz Volcano, Colombia

Londoño

Sudo

2002

Bull Volcanol

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The coda Q has been calculated for Nevado del Ruiz Volcano, Colombia (NRV) from 1985 to 1999 by using a single scattering model. During this period, the inverse of Q (Q -1 proportional to attenuation) exhibited a long-term decrease with time, as well as shorterterm variations related to the volcanic activity. Q -1 increased prior to volcanic crises and decreased afterward. Based on these observations, a seismic warning criterion has been developed. The parameters (frequency band, size of moving average window, and threshold levels) necessary to evidence clear and significant short-term changes in Q -1 have been investigated and appropriated values are proposed. We suggest a phenomenological model with three stages for the short-term temporal changes in Q -1 at NRV. Firstly, Q -1 increases before a volcanic crises because of accumulation of gas and/or liquid, which decreases the aspect ratio of fluid pockets and increases the fractional volume of fluid in the rocks and the pore aspect ratio. Secondly, Q -1 starts to decrease during the crises by the discharging of fluids such as gas, water, etc. from the volcano. Finally, Q -1 becomes more stable after the crisis at a lower value because of the degassing and/or increasing of rigidity of the medium because of the long-term crystallization and cooling processes. Q -1 seems to be a promising monitoring tool at NRV. It is possible that the observed temporal changes of Q -1 , combined with other parameters, may help to predict with greater accuracy a volcanic crisis at NRV.Keywords Coda Q · Fluid aspect ratio · Pore aspect ratio · Seismicity · Volcanic activity Method, data, and processingThe method used to calculate coda Q in this study is based on the assumption that coda waves are single S to Editorial responsibility: J.-F. Lénat

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Eruption of the Nevado del Ruiz Volcano, Colombia, On 13 November 1985: Tephra Fall and Lahars

Cited by 143 publications

References 6 publications

A unified, long‐term, high‐latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology

A unified, long‐term, high‐latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology

Mechanisms of degassing at Nevado del Ruiz volcano, Colombia

A warning model based on temporal changes of coda Q for volcanic activity at Nevado Del Ruiz Volcano, Colombia

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