Castruccio A. auteur aut IRD Clavero J. auteur aut IRD Segura A. auteur aut IRD Samaniego Pablo auteur aut IRD Roche Olivier auteur aut IRD Le Pennec Jean-Luc auteur aut IRD Droguett B. auteur aut IRD text journalArticle eng text/pdf born digital access We conducted geological and petrological analyses of the tephra fallout and pyroclastic density current (PDC) products of the 22-23 April 2015 Calbuco eruptions. The eruptive cycle consisted of two sub-Plinian phases that generated > 15 km height columns and PDCs that travelled up to 6 km from the vent. The erupted volume is estimated at 0.38 km(3) (non-DRE), with approximately 90% corresponding to tephra fall deposits and the other 10% to PDC deposits. The erupted products are basaltic-andesite, 54-55 wt.% SiO2, with minor amounts of andesite (58 wt.% SiO2). Despite the uniform composition of the products, there are at least four types of textures in juvenile clasts, with different degrees of vesicularity and types and content of crystals. We propose that the eruption triggering mechanism was either exsolution of volatiles due to crystallization, or a small intrusion into the base of the magma chamber, without significant magma mixing or with a magma compositionally similar to that of the residing magma. In either case the triggering mechanism generated convection and sufficient overpressure to promote the first eruptive phase. The start of the eruption decompressed the chamber, promoting intense vesiculation of the remaining magma and an increase in eruption rate towards the end of the eruption. specialized Calbuco volcano Southern Andes Sub-Plinian eruption Triggering mechanisms CHILI ANDES CALBUCO VOLCAN 066 78 9 art. 62 [19 p.] 2016 0258-8900 https://www.documentation.ird.fr/hor/fdi:010068150 10.1007/s00445-016-1058-8 0258-8900 [F B010068150] https://www.documentation.ird.fr/hor/fdi:010068150 https://www.documentation.ird.fr/intranet/publi/2016/10/010068150.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2016-11-03 2017-08-23 fdi:010068150 fre