Bulletin of Volcanology

, Volume 68, Issue 4, pp 377–393 | Cite as

Temporal development of the 1999 intrusive episode in the Eyjafjallajökull volcano, Iceland, derived from InSAR images

  • Rikke PedersenEmail author
  • Freysteinn Sigmundsson
Research Article


Eyjafjallajökull volcano, located in southern Iceland, is characterized by its quiet nature. Only about a handful of earthquakes associated with the volcanic system had been detected prior to the 1990s. Earthquake swarms did, however, occur in 1994 and 1999. Here we investigate the spatio-temporal evolution of a magmatic intrusion associated with the 1999 earthquake swarm via analysis of produced surface deformation. A series of interferometric synthetic aperture radar (InSAR) images, spanning various periods of the intrusion, show that in 1999 surface deformation occurred mainly on the southern flanks of the volcano. The deformation amounts to more than 20 cm of range change. Inverse modeling resolves the deformation source to be a sill intrusion at 6.3 km depth. Sill opening was up to 1 m and the total intruded volume amounts to ∼0.03 km3. The InSAR data display a migration of the center of deformation through time, enabling us to create time-dependant sill-opening models. Furthermore, we investigate the spatio-temporal distribution of earthquakes and find that the distribution supports the InSAR derived model and additionally provides indications for a possible site of a feeder channel. Magmatic flow-rate estimates indicate an initial intrusion rate of 4–6 m3/s, declining over a few weeks.


Iceland volcano Intrusion Sill Seismic swarm Deformation InSAR 



We thank Editor Hiroshi Shinohara, reviewer Akira Takada as well as an anonymous reviewer for suggestions which helped to improve the paper. Alan Linde, Tim Wright, Páll Einarsson and Thóra Árnadóttir are thanked for valuable comments on an earlier version of the manuscript. We thank Bryndís Brandsdóttir for scientific discussions and access to unpublished earthquake locations. Kristín Vogfjörd and Erik Sturkell from the Icelandic Meterological Office are thanked for supplying data from the SIL network and GPS data, respectively. ERS SAR images were provided through ESA Envisat grant A03-22 and ERS grant A03-200. Personal grants to RP from the Icelandic science foundation (Rannís, Grants 020110002 and 040202041) and to FS from the University of Iceland Research Fund are acknowledged, as well as support from the EU-supported RETINA project (grant EVG1-CT-0044) and PREPARED project (grant EVG1-CT-2002-00073). The GMT public domain software was used to prepare Fig. 1.


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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Nordic Volcanological Center, Institute of Earth SciencesUniversity of IcelandReykjavíkIceland

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