Present day geodynamics in Iceland monitored by a permanent network of continuous GPS stations

International audience Iceland is located on the Mid-Atlantic Ridge and thereby offers a rare opportunity to study crustal movements at a divergent plate boundary. Iceland is not only characterized by the divergence of the Eurasian and North American Plates, as several active volcanoes are located o...

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Bibliographic Details
Published in:Journal of Geodynamics
Main Authors: Völksen, Christof, Árnadóttir, Thóra, Geirsson, Halldór, Valsson, Guðmundur
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2009
Subjects:
Online Access:https://hal.archives-ouvertes.fr/hal-00594416
https://hal.archives-ouvertes.fr/hal-00594416/document
https://hal.archives-ouvertes.fr/hal-00594416/file/PEER_stage2_10.1016%252Fj.jog.2009.09.033.pdf
https://doi.org/10.1016/j.jog.2009.09.033
Description
Summary:International audience Iceland is located on the Mid-Atlantic Ridge and thereby offers a rare opportunity to study crustal movements at a divergent plate boundary. Iceland is not only characterized by the divergence of the Eurasian and North American Plates, as several active volcanoes are located on the island. Moderate size earthquakes occur in the transform zones, causing measurable crustal deformation. In 1999 the installation of a permanent network of continuous GPS stations (ISGPS) was initiated in order to observe deformation due to unrest in the Hengill volcanic system and at the Katla volcano. The ISGPS network has been enlarged over the years and consists today of more than 25 CGPS stations. Most of the stations are located along the plate boundary, where most of the active deformation takes place. Uplift due to post-glacial rebound due to the melting of the largest glacier in Europe, Vatnajökull, is also detected by the ISGPS network. This study presents results from analysis of nine years of data from the ISGPS network, in the global reference frame PDR05, which has been evaluated by the Potsdam-Dresden-Reprocessing group with reprocessed GPS data only. We thus determine subsidence or land uplift in a global frame. The horizontal station velocities clearly show spreading across the plate boundary of about 20mm/a. Stations in the vicinity of the glacier Vatnajökull indicate uplift in the range of 12mm/a, while a station in the central part of Iceland shows uplift rates of about 25mm/a. Tide gauge readings in Reykjavik and current subsidence rates observed with CGPS agree also quite well.