Artículos científicos

URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/17882

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Gas measurements from the Costa Rica–Nicaragua volcanic segment suggest possible along-arc variations in volcanic gas chemistry
(Elsevier, 2014) Aiuppa, A.; Robidoux, P.; Tamburello, G.; Conde, V.; Galle, B.; Avard, G.; Bagnato, E.; De Moor, J. M.; Martínez, M.; Muñoz, A.
Obtaining accurate estimates of the CO2output from arc volcanism requires a precise understanding of the potential along-arc variations in volcanic gas chemistry, and ultimately of the magmatic gas signature of each individual arc segment. In an attempt to more fully constrain the magmatic gas signature of the Central America Volcanic Arc (CAVA), we present here the results of a volcanic gas survey performed during March and April 2013 at five degassing volcanoes within the Costa Rica–Nicaragua volcanic segment (CNVS). Observations of the volcanic gas plume made with a multicomponent gas analyzer system (Multi-GAS) have allowed characterization of the CO2/SO2-ratio signature of the plumes at Poás (0.30 ±0.06, mean ±SD), Rincón de la Vieja (27.0 ±15.3), and Turrialba (2.2 ±0.8) in Costa Rica, and at Telica (3.0 ±0.9) and San Cristóbal (4.2 ±1.3) in Nicaragua (all ratios on molar basis). By scaling these plume compositions to simultaneously measured SO2fluxes, we estimate that the CO2outputs at CNVS volcanoes range from low (25.5 ±11.0tons/day at Poás) to moderate (918 to 1270 tons/day at Turrialba). These results add a newinformation to the still fragmentary volcanic CO2output data set, and allow estimating the total CO2output from the CNVS at 2835 ±1364tons/day. Our novel results, with previously available information about gas emissions in Central America, are suggestive of distinct volcanic gas CO2/ST(=SO2+H2S)-ratio signature for magmatic volatiles in Nicaragua (∼3) relative to Costa Rica (∼0.5–1.0). We also provide additional evidence for the earlier theory relating the CO2-richer signature of Nicaragua volcanism to increased contributions from slab-derived fluids, relative to more-MORB-like volcanism in Costa Rica. The sizeable along-arc variations in magmatic gas chemistry that the present study has suggested indicate that additional gas observations are urgently needed to more-precisely confine the volcanic CO2from the CAVA, and from global arc volcanism.
Insights on Hydrothermal‐Magmatic Interactions and Eruptive Processes at Poás Volcano (Costa Rica) From High‐Frequency Gas Monitoring and Drone Measurements
(AGU Publications, 2019-02-06) De Moor, J. M.; Stix, J.; Muller, C.; Corrales, E.; Diaz, J. A.; Alan, A.; Brenes, J.; Pacheco, J.; Aiuppa, A.; Fischer, T. P.; Avard, Geoffroy
Identification of unambiguous signals of volcanic unrest is crucial in hazard assessment. Processes leading to phreatic and phreatomagmatic eruptions remain poorly understood, inhibiting effective eruption forecasting. Our 5‐year gas record from Poás volcano, combined with geophysical data, reveals systematic behavior associated with hydrothermal‐magmatic eruptions. Three eruptive episodes are covered, each with distinct geochemical and geophysical characteristics. Periods with larger eruptions tend to be associated with stronger excursions in monitoring data, particularly in SO2/CO2 and SO2 flux. The explosive 2017 phreatomagmatic eruption was the largest eruption at Poás since 1953 and was preceded by dramatic changes in gas and geophysical parameters. The use of drones played a crucial role in gas monitoring during this eruptive period. Hydrothermal sealing and volatile accumulation, followed by top‐down reactivation of a shallow previously emplaced magma body upon seal failure, are proposed as important processes leading to and contributing to the explosivity of the 2017 eruption.

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Examinando Artículos científicos por Autor "Aiuppa, A."