Acoustic observations of lava fountain activity during the 2021 Fagradalsfjall eruption, Iceland

Abstract

Fagradalsfjall Lava Fountain Acoustics the lava fountain sequence. Finally, we propose that higher acoustic amplitudes, in addition to a wider conduit in late May, indicates higher gas flux through the conduit culminating in shorter lava fountain events. This study highlights the value of deploying acoustic sensors for providing additional constraints on eruption dynamics and source parameters during effusive fissure eruptions in Iceland and elsewhere.

Evolving shallow conduit revealed by tremor and vent activity observations during episodic lava fountaining of the 2021 Geldingadalir eruption, Iceland

“…Episodic fountaining, steady magma flow and heat mechanically erode and enlarge the vent and conduit. Note that Lamb et al (2022) arrived at the same conclusion based on independent infrasound data. This enlargement reflects in larger seismic amplitudes as long as major collapses do not interfere with the vent dimensions.…”

Lava fountain jet noise during the 2018 eruption of fissure 8 of Kīlauea volcano

“…In particular the spectral shape of volcanic eruption noise is remarkably similar to jet noise (Matoza et al, 2009(Matoza et al, , 2013Gestrich et al, 2021). Lava fountains are a specific expression of sustained eruptions, and due to their diversity in dynamics, multiple source generation mechanisms have been proposed such as oscillatory motion of lava during churn flow Ulivieri et al (2013), bubble bursting, and also jet noise (Lamb et al, 2022). By understanding the source of the acoustics recorded during lava fountain activity, we may connect changes of acoustic parameters to changes in the lava fountain dynamics.…”

“…Video, radar, gas sampling, and other techniques provide insight into fountain dynamics but are hampered by measurement uncertainties and deployment and safety challenges (Evans and Staudacher, 2001;Witt and Walter, 2017;Mereu et al, 2020). Infrasound provides one technique for examining lava fountains, as they can be prolific producers of low-frequency and audible acoustic waves (e.g., Fee et al, 2011;Sciotto et al, 2019;Lamb et al, 2022). Here, we will use the analogy between laboratory jets and the gas release during lava fountain events to determine the gas velocity and vent diameter.…”

“…Fine scale turbulence (FST) noise, on the other hand, is produced by small incoherent turbulent motion and dominates outside of the LST cone. The spectral shapes described by (Tam et al, 1996) have been used to identify low frequency jet noise during volcanic eruptions (e.g., Matoza et al, 2009Matoza et al, , 2013Taddeucci et al, 2014;Gestrich et al, 2021;Lamb et al, 2022). Jet flow can exhibit a variety of other features that produce acoustic signals such as the vortex ring at the beginning of the jet formation (Fernández and Sesterhenn, 2017;Taddeucci et al, 2021) and crackle during supersonic jet flow .…”

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

“…Beyond the traditional designation of eruption styles based on visual observation of eruptions at type localities, eruption imaging and geophysical recording are currently pushing toward more quantitative definitions of explosive eruptions. Recent advances in eruption imaging, in particular, have extensively helped parameterizing explosive activity at several volcanoes, including, but not limited to, Stromboli (Italy) (e.g., Bombrun et al., 2015; Pering et al., 2020; Ripepe et al., 1993; Taddeucci, Scarlato, et al., 2012), Yasur (Vanuatu) (Gaudin et al., 2017; Simons, Cronin, Eccles, Bebbington, & Jolly, 2020; Simons, Cronin, Eccles, Jolly, et al., 2020; Spina et al., 2015), Reunion (France) (Edwards et al., 2020), Etna (Italy) (Pering et al., 2014; Pioli et al., 2022; Spina et al., 2017), Batu Tara (Indonesia) (Spina et al., 2021), Fuego (Guatemala) (Marchetti et al., 2009), Kilauea (USA) (Gestrich et al., 2022; Houghton et al., 2021; Mintz et al., 2021; Patrick et al., 2019), and Eyjafjallajökull and Fagradalsfjall (Iceland) (Dürig, Gudmundsson, Karmann, et al., 2015; Dürig, Gudmundsson, & Dellino, 2015; Lamb et al., 2022). These eruption imaging and geophysical studies have largely contributed to understanding the underlying processes and defining more systematically eruption styles of mafic explosive activity, mostly Hawaiian and Strombolian ones.…”