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Tremor amplitude associated with boiling lava pond activity during the 2021 Geldingadalir eruption

Alea Joachim 1, Eva P. S. Eibl1, Daniel Müller2, Thomas R. Walter2,1, Tom Winder3, Nicholas Rawlinson4

  • Affiliations: 1Institute for Geosciences,University of Potsdam, Potsdam, Germany; 2GFZ Helmholtz Centre for Geosciences, Potsdam, Germany; 3University of Iceland, Reykjavik, Iceland; 4University of Cambridge, Cambridge, United Kingdom

  • Presentation type: Talk

  • Presentation time: Friday 10:45 - 11:00, Room S150

  • Programme No: 3.17.2

  • Theme 3 > Session 17

Abstract

Volcanic tremor is a common signal during volcanic eruptions, but the underlying mechanisms of tremor are still not well understood. In 2021, an eruption with episodic lava effusion began in the Geldingadalir valley in Iceland. Here, we examine the tremor signal associated with episodic lava effusion on 8 June 2021, using a combination of photogrammetric data, drone video footage, and seismic tremor recordings from a seismometer near the eruption site, to investigate the timing of the tremor, eruption, and lava pond fluctuations. Our analysis reveals a distinct pattern of tremor episodes, with an average duration of 5 minutes followed by 7-minute repose. However, a closer examination of the drone video footage of one effusion episode shows that the lava pond undergoes significant fluctuations, rising and falling about 24.6 metres within 12 minutes. While the rise of the lava pond is relatively slow, taking about 10 minutes, the fall of the pond level is rapid, taking less than 2 minutes. Thus, the tremor amplitude does not correlate with the pond level, but rather peaks when the bubble bursting and spattering activity in the pond is most intense. This suggests that the tremor is closely linked to bubble bursting activity, providing insight into near-surface processes during effusive eruptions. This has important implications for understanding dynamic changes in lava ponds.