INENCO   05446
INSTITUTO DE INVESTIGACIONES EN ENERGIA NO CONVENCIONAL
Unidad Ejecutora - UE
artículos
Título:
Eruption dynamics of the 22-23 April 2015 Calbuco Volcano (Southern Chile): Analyses of tephra fall deposits
Autor/es:
MORGAVI, DANIELE; CASELLI, ALBERTO; DÍAZ-ALVARADO, JUAN; PERUGINI, DIEGO; ARZILLI, FABIO; ARZILLI, FABIO; RECKZIEGEL, FLORENCIA; RECKZIEGEL, FLORENCIA; POLACCI, MARGHERITA; POLACCI, MARGHERITA; ROMERO, JORGE; DAGA, ROMINA; VIRAMONTE, JOSÉ; BURTON, MIKE; ROMERO, JORGE; DAGA, ROMINA; VIRAMONTE, JOSÉ; BURTON, MIKE; MORGAVI, DANIELE; CASELLI, ALBERTO; DÍAZ-ALVARADO, JUAN; PERUGINI, DIEGO
Revista:
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2016 vol. 317 p. 15 - 29
ISSN:
0377-0273
Resumen:
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 (N15 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 showfield 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 paroxysmalevent (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.