On or Off? Interpreting episodic tremor during the Fagradalsfjall eruption 2021

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• Eva P. S. Eibl - University of Potsdam
• Wednesday 15 March 2023, 16:00-17:00
• Wolfson Lecture Theatre.

If you have a question about this talk, please contact Yihe Xu.

The Fagradalsfjall eruption on the Reykjanes peninsula, Iceland, lasted from 19 March to 18 September 2021. While it continuously effused lava at the beginning, it opened up 7 further vents in April and focused the activity from late April on Vent 5. Surprisingly the continuous effusion changed to episodic lava effusion (as lava fountains or vigorous overflow) between 2 May and 14 June and 2 July to 18 September. This was recorded seismically as tremor episodes. We examined the frequency of more than 10000 lava fountaining episodes based on seismological data recorded at 5.5 km and 2 km from the active vent.

We subdivide the time interval into 9 periods based on sudden changes in the fountaining duration, repose time and seismic amplitude. We observed minute-long, hour-long and one-week-long episodes as well as minute-long to hour-long to week-long repose times. In addition, for about 6 days it featured short and long episodes at the same time much like geyser Strokkur (see Eibl et al. 2020)! So what triggered these changes and how can we interpret these changes? I will discuss this in my presentation and will use some figures from our publication in review with Bull. Volc (see link below).

Link to paper in review

This talk is part of the Bullard Laboratories Wednesday Seminars series.

This talk is included in these lists:

• Bullard Laboratories Wednesday Seminars
• Department of Earth Sciences seminars
• Wolfson Lecture Theatre

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