Skip to content

Eruptive dynamics of a long-lasting, hybrid eruption: physical and textural characterization of the 2021 Tajogaite eruption (La Palma, Spain)

Marija Voloschina1 , Serena Da Mommio1, Beverley C. Coldwell2,3, Alessandro Vona4, Nemesio M. Pérez2,3, Costanza Bonadonna5, Marco Pistolesi1

  • Affiliations:  1Department of Earth Sciences, University of Pisa, Pisa, Italy; 2Instituto Volcanológico de Canarias (INVOLCAN), Puerto de la Cruz, Tenerife, Canary Islands, Spain; 3Environmental Research Division, Instituto Tecnológico y de Energías Renovables (ITER), Granadilla de Abona, Tenerife, Canary Islands, Spain; 4Dipartimento di Scienze, Università degli Studi Roma Tre, Roma, Italy; 5Department of Earth Sciences, University of Geneva, Geneva, Switzerland 

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 237

  • Programme No: 1.6.13

  • Theme 1 > Session 6

Abstract

Hybrid eruptions comprise of effusive and explosive behaviour occurring simultaneously or in quick succession. In long-term records, this activity tends to be overlooked due to the challenges of identifying simultaneous activity from deposits. Therefore, the study of tephra sequences associated with well-documented hybrid eruptions is particularly valuable. The recent Tajogaite eruption (Canary Islands) lasted for 86 days and the eruptive activity consisted of effusive activity from the base of the newly-formed cone and contemporaneous explosive activity from the summit vents. A textural, morphological and geochemical characterization of the juvenile material ejected during the Tajogaite eruption is presented to frame changes in eruptive dynamics and underlying conduit processes. We distinguish three eruptive phases: the high intensity Phase I contains highly vesicular clasts of irregular to spongy morphology and a wide range in vesicularity (⁓55-68%), while volume-normalised vesicle numbers NVm show limited variability (11.4-16.6 × 106 cm-3). Phase II marks an overall decrease in eruption intensity towards more intermittent activity. The associated juvenile material shows a lower, limited vesicularity, with variable NVm and irregular to subspherical morphologies. In the final Phase III, eruption intensity increases again, with pyroclasts displaying variable morphologies, high NVm values (24-85.2 × 106 cm-3), and ⁓60% vesicularity. The observed morphological and textural variability of the tephra indicate syn-eruptive changes in the conduit that can be related to the presence of multiple, simultaneously active conduits with different geometries. These exert a temporally and spatially variable control on magma outgassing, fragmentation and crystallization, resulting in the observed hybrid activity.