The Explosive Activity of the 2021 Tajogaite Eruption (La Palma, Canary Islands, Spain)

Abstract

The explosive activity of the 2021 Tajogaite eruption eludes pigeonholing into well‐defined eruption styles, with a variety of pyroclast ejection modes occurring both alternately and simultaneously at multiple vents. Visually, we defined four endmembers of explosive activity, referred to as fountaining, spattering, ash‐poor jets and ash‐rich jets. To capture the physical parameters of these activities, we deployed a camera array including one high‐speed camera and three high‐definition cameras in two field campaigns. Transitions between and fluctuations within activity occurred at the time scale of minutes to hours, likely driven by the same shallow conduit and vent processes controlling Strombolian activity at other volcanoes, but at higher gas and magma fluxes. From a physical standpoint, mean pyroclast rise velocity ranged 5–50 m/s, maximum ejection velocity 10–220 m/s, and sub‐second mass flux of lapilli to bomb‐sized pyroclasts at the vent 0.2–200 × 103 kg/s. The largest mass flux occurred during fountaining, which contributed by far more than other activities to cone building. All explosive activity exhibited well‐defined pyroclast ejection pulses, and we found a positive correlation between the occurrence rate of ejection pulses and maximum pyroclast ejection velocity. Despite orders of magnitude variations, physical parameters shift gradually with no boundary from one activity endmember to another. As such, attributing this explosive activity specifically to any currently defined style variations is arbitrary and potentially misleading. The highly variable explosive activity of the Tajogaite eruption recalls previous definitions of violent Strombolian eruptions, an eruption style whose pyroclast ejection dynamics, however, were so far largely undefined.

Magma residence time, ascent rate and eruptive style of the November ash-laden activity during the 2021 Tajogaite eruption (La Palma, Spain)

“…In agreement with previous works [e.g. Bonadonna et al 2022;González-García et al 2023;Taddeucci et al 2023], the results of our study suggest that transitions in eruptive style during the Tajogaite eruption are likely the result of a complex feedback between several factors, including gas emission rate, fractionation of gas and magma between explosive and effusive vents, changes in conduit geometry, and magma ascent rates.…”

“…Indeed, during 15 November, but also reported for other days of activity in the second half of the eruption, the occurrence of explosive activity characterized by the ejection of abundant dark ash and a strongly subordinate amount of visible lapilli and small bombs, with formation of low (≲ 1-2 km), wind-bent plumes, was observed. This activity corresponds to the ash-rich jets reported in Taddeucci et al [2023] and cannot be solely explained by considering the physicochemical characteristics of the November magma, which, besides the more primitive composition, are similar to those of the early phases of the eruption. We suggest that the triggering mechanisms of such explosive activity might be linked to a smaller conduit geometry, ejecta fallen back in the crater that created an obstruction, favouring gas entrapment and fragmentation, and/or lower gas emission rates.…”

“…The eruption has been described as hybrid [Bonadonna et al 2022] because of the simultaneous occurrence of lava flows and tephra from multiple vents mostly associated with a variety of eruptive styles (e.g. lava flows, ash emissions, lava fountains, Strombolian activity), often alternating at different vents as well as at the same vent [Longpré and Felpeto 2021;Bonadonna et al 2022;Pankhurst et al 2022;Romero et al 2022;Taddeucci et al 2023]. Col-Figure 1: Chronology of the eruptive activity during 13-18 November.…”

The spatiotemporal evolution of compound impacts from lava flow and tephra fallout on buildings: lessons from the 2021 Tajogaite eruption (La Palma, Spain)

“…The eruption consisted of the simultaneous emission of lava flows and a range of low to moderate explosive styles ranging from Hawaiian (i.e. sustained fountaining) to violent Strombolian activity (Bonadonna et al 2023 ; Taddeucci et al 2023 ). The final ~ 1.8 × 10 8 m 3 lava flow field was emplaced over an area of 12 km 2 , and the volume of the tephra blanket was estimated to be ~ 2.3 × 10 7 m 3 (Bonadonna et al 2022 ; Civico et al 2022 ; Fig.…”

Magma Differentiation in Dynamic Mush Domains From the Perspective of Multivariate Statistics: Open‐ Versus Closed‐System Evolution

“…This volcanic regime characterizes several of the most hazardous volcanic areas worldwide, such as Fuego, Guatemala (Liu et al., 2020), Batu Tara, Indonesia (Spina et al., 2021), Mt. Etna, Italy (Di Renzo et al., 2019; Mollo et al., 2022), Cumbre Vieja, Spain (Di Fiore, Vona, Mollo, et al., 2023; Di Fiore, Vona, Scarani, et al., 2023; Taddeucci et al., 2023; Ubide et al., 2023). Quantitative modeling of magma differentiation in open‐systems highlights that the liquid lines of descent substantially depart from standard fractional crystallization scenarios (Albarede, 1985; Lee et al., 2014; O’Hara, 1977; O’Hara & Mathews, 1981; O’Hara & Herzberg, 2002; O’Neill & Jenner, 2012).…”