ALBERT

Description: The 2021 hybrid Tajogaite eruption of Cumbre Vieja (La Palma) was mainly effusive, with 〉70% of volume erupted as lava and simultaneous explosive activity with variable eruptive styles (e.g., Strombolian, violent Strombolian, lava fountaining, ash-poor gas puffing) depositing a widespread tephra blanket. Tephra dispersal and grainsize features indicate violent Strombolian dynamics when field-based classification schemes are used. Statistical analyses of pulsatory activity indicate short-time fluctuations amongst the observed multiple eruptive styles, suggesting rapid gas segregation and high magma ascent rate modulating magma fragmentation and conduit dynamics distributed at the different vents. Pulsatory activity and variable eruptive style affected tephra sedimentation causing unsteady tephra ground accumulation across time. Various sedimentation processes were observed, including particle aggregation (especially in case of rainy atmospheric conditions) and different types of sedimentation features (e.g., lapilli waves, ash fingers). The tephra blanket, with a volume of ~2×10〈sup〉7〈/sup〉 m〈sup〉3〈/sup〉, was mostly dispersed NE-SW due to the complex regional and local wind patterns and was subdivided into three units and eleven layers that well correlate at different distances from the vent and agree with both seismic tremor data and lava emission rates. Grainsize distributions at individual locations are unimodal, with Mdf increasing and sorting decreasing with distance from the vents. Total grainsize distributions of selected layers, units, and the whole tephra blanket are unimodal with Mdphi values between -0.5 and 1.4 phi (1.4-0.4 mm). Evidence of the Tajogaite eruption dynamics highlight the challenges of risk and crisis management associated with long-lasting basaltic pulsatory hybrid eruptions.