Methodology/work description

Input to WP 3 includes all accessible geodetic data regarding crustal deformation in Iceland, collected previously by partners of the proposal, other agencies in Iceland, and agencies elsewhere. Currently the raw observational data are distributed in a number of institutes, and only some of the observational results have been published. Because of its poor accessibility, the complete dataset of crustal deformation in Iceland is of limited benefit for the partners of this proposal, and other scientists in Europe. We will change this by creating and maintaining an Icelandic geodetic database. Importantly, partner 5 will utilize his good contacts with most groups involved in collecting geodetic data in Iceland, ensuring they will provide all, or significant part, of their geodetic data as an input into the database.

Deformation studies by repeated GPS measurements have been carried out in Iceland since 1986 by several groups. They have shown significant variability of deformation rates, both in time and space. This technique has successfully been used for deformation studies and modeling of rifts, transform and volcanic zones in Iceland. All GPS data previously acquired in Iceland potentially represent an opportunity to have a coverage of the deformation at a large-scale.

Semi-continuous GPS measurements at one SIL station in the South Iceland seismic zone have shown the overall plate motion. Continuous GPS measurements (CGPS) is an extremely valuable method to provide temporal coverage of the deformation, in addition to borehole volumetric strainmeter recordings. CGPS measurements have been initiated for seismic and volcanic risk mitigation purposes at four sites in the Hengill area, Southwest Iceland. Four other CGPS stations are planned in the seismic risk area near Húsavík, North Iceland, also for that purpose. Two CGPS stations in South Iceland are currently operated by the IGS and EUREF permanent networks, for determining coordinates and velocities of reference points and satellite orbits. These new CGPS stations create a start, but an incomplete network of CGPS in Iceland. Because of the significant build-up and operation of continuous deformation measurements already in the lowland seismic risk areas of Iceland it is a scientific necessity to improve the infrastructure with CGPS stations where we most probably could observe, localize, and quantify the initial effects of crustal deformation related to the mantle plume activity, that is near the Hotspot center, in the highlands. To reach this goal we will start to collect and process data from CGPS stations in Iceland and unite all ongoing CGPS networks in Iceland. We also propose to improve the infrastructure in the highlands and install facilities to encourage scientists and surveyors to temporarily leave their GPS instruments in the network for semi-continuous measurements.