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How may syneruptive cone collapse modify the eruption column in basaltic eruptions?

Simona Scollo1 , Francesco Amadio2, Luigi Mereu3,5, Samuele Pili2, Veronica Pili2, Francesco Romeo1,4,5, Laura Pioli2 ^ ^

  • Affiliations: 1Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, Catania, Italy;2Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Italy;3Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Italy;4Dipartimento di Ingegneria dell'Informazione, Elettronica e Telecomunicazioni, Sapienza Università di Roma, Italy; 5Centre of Excellence CETEMPS, University of L'Aquila, Italy

  • Presentation type: Talk

  • Presentation time: Friday 11:00 - 11:15, Room S150

  • Programme No: 3.17.3

  • Theme 3 > Session 17

Abstract

Basaltic explosive eruptions can generate eruption columns several kilometres high, dispersing lapilli and ash across areas spanning tens of square kilometres. At frequently erupting volcanoes like Etna, in Italy, these eruptions are often accompanied by lava flows and may trigger cone instabilities that travel downslope, potentially interacting with the ash-rich column erupted from the vent. In this study, we analyse the lava fountain occurred on February 10, 2022. During this eruption, the volcanic cloud was dispersed toward the northern coast of Sicily. This event was associated with a partial cone collapse and the formation of hot, dense flows that extended few kilometres beyond the summit area. Using data from cameras, radar, and satellites, we quantify for the first time how the cone collapse influenced the dynamics of the eruption column and the associated tephra deposit. Tephra deposit was sampled at distances ranging from 1 to 23 kilometres from the vent. We estimated a total mass of 1.20 - 9.48 × 109 kg. The total grain-size distribution of the deposit was bimodal and the component analysis revealed a composition dominated by sideromelane. Our findings indicate that the total mass and mass eruption rate were comparable to the largest lava fountain events at Etna over the past decade. Additionally, the presence of the hot flows increased the column height by less than 2 km and slightly altered the total grain-size distribution. We believe this study gives valuable insights into the influence of cone collapse on eruption column dynamics and tephra dispersal processes.