%0 Journal Article
%A Calvari, Sonia
%A Ganci, Gaetana
%A Galindo, Inés
%A Sanz Mangas, David
%A Morgavi, Daniele
%A Fernandez Lorenzo, Octavio
%T Emplacement and growth of a stacked tube-fed lava flow field: the 2021 Tajogaite eruption (La Palma, Canary Islands, Spain)
%D 2025
%@ 0258-8900
%U https://hdl.handle.net/20.500.14352/132052
%X On 19 September 2021, the Cumbre Vieja volcano in the southern part of La Palma (Canary Islands) erupted after 50 years of quiescence. A northwest-southeast eruptive fissure opened on the west flank of the volcano, producing explosive and effusive activity that lasted until 13 December 2021. The explosive activity from the fissure built up a new cone named Tajogaite, and the discharge of high temperature and low viscosity magma gave rise to lava flows. These spread from the base of the cone to the west, reaching the sea and forming a complex lava flow field with the stacking of flows and lava tube pathways. The eruption caused the destruction of 2988 buildings and ~ 12 km2 of urbanized areas, farmland, and plantations, emplacing ~ 200 × 106 m3 lava and ~ 45 × 106 m3 tephra, with ~ 5 × 106 m3 lava forming a lava delta. This eruption offered a unique opportunity to study the emplacement of a complex lava tube network developed initially within ‘a‘ā arterial flows and later on within pāhoehoe flows. We present an account of the expansion of the lava flow field and of the development of lava tubes gathered from satellite images and field surveys. We go on to characterize the processes of lava flow field development and lava tube formation and growth and estimate the time-averaged discharge rate and erupted lava volume. From the start of the eruption to the end of October, the lava flow field was mainly characterized by the emplacement of four sequential ‘a‘ā arterial flows. Along these flows, master lava tubes rapidly developed by the roofing-over of lava channels within a few days from their emplacement. The ‘a‘ā arterial flows advanced in a caterpillar-like fashion, alternating proximal lava channel overflows and drainage corresponding to the slowing down and accelerating of the lava front. From November to the end of the eruption, a decreased discharge rate resulted in the output of mainly pāhoehoe flows emplaced in the medial portion of the lava flow field. Overlapping ‘a‘ā and pāhoehoe flow units formed stacked tube systems. Our results highlight the speed and processes of lava flow field development and lava tube growth during an effusive eruption on a steep slope (> 4°), the complexity of lava tubes at multiple levels in a stacked flow sequence, and provide useful information for hazard mitigation should a new eruption occur in this area or on other steep volcanoes.
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