Post-Rifting Relaxation During 2015–2020 Following the Bárðarbunga-Holuhraun Dike Intrusion and Eruption in Iceland

Siqi Li*, Ronni Grapenthin, Freysteinn Sigmundsson, Vincent Drouin, Sigrún Hreinsdóttir, Benedikt G. Ófeigsson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Post-rifting ground deformation may be driven by viscoelastic relaxation of stresses generated by dike intrusions. The single-dike intrusion of the 2014–2015 Bárðarbunga eruption in Iceland presents an opportunity for a detailed study of this process. We use continuous Global Navigation Satellite System (GNSS) and Interferometric Synthetic Aperture Radar (InSAR) velocity fields to analyze the 2015–2020 post-rifting deformation, showing uplift on both sides of the dike and horizontal displacement away from the dike after correcting for background deformation. Two GNSS stations experience baseline lengthening at a rate of 19 mm/yr in the direction perpendicular to the strike of the dike. A two-layer viscoelastic model with a 0.4 × 1019 Pa s viscoelastic half-space overlain by an 18 km thick elastic layer best explains the observed horizontal and vertical InSAR and GNSS displacements. The model misfit space shows a second regime of good fit, likely driven by deformation near the dike that may result from cooling compaction of the emplaced dike.

Original languageEnglish
Article numbere2022GL098977
JournalGeophysical Research Letters
Issue number13
Publication statusPublished - 12 Jul 2022

Bibliographical note

Funding Information:
We thank the Research Fund of the University of Iceland for funding for the Ph.D. work of the first author (S. Li), of which this research is a part of. Partial financial support from the H2020 project EUROVOLC funded by the European Commission is acknowledged (Grant No. 731070). R. Grapenthin acknowledges partial support for this work through NSF grant EAR‐1464546. We thank Chiara Lanzi for helping to benchmark the dike model. We thank the fruitful discussion with Halldór Geirsson and Andrew Hooper. We thank the reviewer for the constructive comments, which helped strengthen our manuscript. We thank the editor and editor's assistant for their time in helping us with this article.

Publisher Copyright:
© 2022. American Geophysical Union. All Rights Reserved.

Other keywords

  • dike
  • GNSS
  • Iceland volcano deformation
  • InSAR
  • post-eruptive deformation
  • viscoelastic relaxation


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