Eruption dynamics of the 22-23 April 2015 Calbuco Volcano (Southern Chile): Analyses of tephra fall deposits

• Autores: Romero Moyano, Jorge; Morgavi, Daniele; Arzilli, Fabio; Daga, Romina Betiana; Caselli, Alberto Tomás; Reckziegel, Florencia Mabel; Viramonte, Jose German; Díaz Alvarado, Juan; Polacci, Margherita; Burton, Mike; Perugini, Diego
• Año de publicación: 2016
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Exactas y Naturales; Calbuco Volcano; Eruption Chronology; Tephra Stratigraphy; SubPlinian Eruption; Ciencias Exactas y Naturales
• Institución: Universidad Nacional de Río Negro

Fil: Romero, Jorge; Saltori. Universidad de Atacama; Chile
Fil: Morgavi, Daniele. Università di Perugia; Italia
Fil: Arzilli, Fabio. University of Manchester; Reino Unido
Fil: Daga, Romina Betiana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.
Fil: Caselli, Alberto Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.
Fil: Reckziegel, Florencia Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina
Fil: Viramonte, Jose German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina
Fil: Díaz Alvarado, Juan. Universidad de Atacama; Chile
Fil: Polacci, Margherita. University of Manchester; Reino Unido
Fil: Burton, Mike. University of Manchester; Reino Unido
Fil: Perugini, Diego. Università di Perugia; Italia
Fil: Daga, Romina Betiana. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina
Fil: Caselli, Alberto Tomás. Universidad Nacional de Río Negro. Río Negro, Argentina
After 54 years since its last major eruption in 1961, Calbuco Volcano (Ensenada, Southern Chile) reawakened with few hours of warning on 22 April 2015 at 18:05 local time. The main explosive eruption consisted of two eruption pulses (lasting ~1.5 and 6 h each one) on 22 and 23 April, producing stratospheric (>15 km height) eruption columns. The erupted materials correspond to porphyritic basaltic andesite (~55 wt.% of SiO2). The tephra fall affected mainly the area northeast of the volcano and the finest ash was deposited over Southern Chile and Patagonia Argentina. We studied the tephra fall deposits of both pulses in terms of stratigraphy, distribution, volume, emplacement dynamics and eruption source parameters. Here, we show field observations that have been made 5-470 km downwind and distinguish five layers (Layers A, B, B1, C and D) representing different stages of the eruption evolution: eruption onset (Layer A; pulse 1), followed by the first paroxysmal event (Layer B; pulse 1), in some places interbedded by layer B1, tentatively representing the sedimentation of a secondary plume during the end of pulse 1. We recognized a second paroxysm (Layer C; pulse 2) followed by the waning of the eruption (Layer D; pulse 2). The total calculated bulk tephra fall deposit volume is 0.27 ± 0.007 km3 (0.11-0.13 km3 dense rock equivalent), 38% of which was erupted during the first phase and 62% during the second pulse. This eruption was a magnitude 4.45 event (VEI 4 eruption) of subPlinian type.
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