Subglacial volcano monitoring with fibre-optic sensing: Grímsvötn, Iceland

We present a distributed acoustic sensing (DAS) experiment at Grímsvötn, Iceland. This is intended to investigate volcano-microseismicity at Grímsvötn specifically, and to assess the suitability of DAS as a subglacial volcano monitoring tool in general. In spring 2021, we trenched a 12 km long fiber...

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Bibliographic Details
Published in:Volcanica
Main Authors: Sara Klaasen, Solvi Thrastarson, Yeşim Çubuk-Sabuncu, Kristín Jónsdóttir, Lars Gebraad, Patrick Paitz, Andreas Fichtner
Format: Article in Journal/Newspaper
Language:English
Published: Volcanica 2023
Subjects:
seismic activity
subglacial
active volcanoes
monitoring
volcano-seismology
Geology
QE1-996.5
Ice Sheet
Iceland
Online Access:https://doi.org/10.30909/vol.06.02.301311
https://doaj.org/article/1fada8d2c5bd4753b38a4066931652f8
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Summary:We present a distributed acoustic sensing (DAS) experiment at Grímsvötn, Iceland. This is intended to investigate volcano-microseismicity at Grímsvötn specifically, and to assess the suitability of DAS as a subglacial volcano monitoring tool in general. In spring 2021, we trenched a 12 km long fiber-optic cable into the ice sheet around and within the caldera, followed by nearly one month of continuous recording. An image processing algorithm that exploits spatial coherence in DAS data detects on average ~100 events per day, almost 2 orders of magnitude more than in the regional earthquake catalog. A nonlinear Bayesian inversion reveals the presence of pronounced seismicity clusters, containing events with magnitudes between −3.4 and 1.7. Their close proximity to surface volcanic features suggests a geothermal origin. In addition to painting a fine-scale picture of seismic activity at Grímsvötn, this work confirms the potential of DAS in subglacial volcano monitoring.

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