HR: 0800h
AN: G21B-1275    [Abstracts]
TI: Crustal Deformation in Iceland Derived from the Nation-wide 1993 and 2004 ISNET Campaigns
AU: * Geirsson, H
EM: dori@vedur.is
AF: Icelandic Meteorological Office, Bustadavegur 9, Reykjavik, 150 Iceland
AU: Árnadóttir, T
EM: thora1@hi.is
AF: Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Sturkell, E
EM: sturkell@hi.is
AF: Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Jiang, W
EM: weiping@hi.is
AF: Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Rennen, M
EM: mr@hnit.is
AF: National Land Survey of Iceland, Stillholt 16-18, Akranes, 300 Iceland
AU: Völksen, C
EM: voelksen@bek.badw-muenchen.de
AF: Bayerische Kommission fuer die Internationale Erdmessung, Bayerische Akademie der Wissenschaften, Marstallplatz 8, Muenchen, D-80539 Germany
AU: Pagli, C
EM: carolina@hi.is
AF: Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Sigurdsson, T
EM: thorarinn@lmi.is
AF: National Land Survey of Iceland, Stillholt 16-18, Akranes, 300 Iceland
AU: Theodorsson, T
EM: teddi@lv.is
AF: National Power Company, Haaleitisbraut 68, Reykjavik, 103 Iceland
AU: Erlingsson, J
EM: jse@vegagerdin.is
AF: Public Roads Administration, Borgartun 5-7, Reykjavik, 105 Iceland
AU: Valsson, G
EM: gudmundur@lmi.is
AF: National Land Survey of Iceland, Stillholt 16-18, Akranes, 300 Iceland
AU: Valsson, G
EM: gudmundur@lmi.is
AF: Institute of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Einarsson, P
EM: palli@raunvis.hi.is
AF: Institute of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Sigmundsson, F
EM: fs@hi.is
AF: Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AB: Until now research on crustal deformation in Iceland has been restricted to limited areas of the plate boundary and/or volcanoes. We present for the first time the deformation field for all of Iceland. The National Land Survey of Iceland maintains a geodetic refence network (ISNET) of more than 120 points distributed evenly across Iceland. The network spans the mid-Atlantic plate boundary and extends up to 200 km into the Eurasian and North American plates. The network was first surveyed in 1993 and again in 2004 in collaboration of a number of Icelandic institutions. The horizontal displacement field is dominated by the spreading of the Mid-Atlantic ridge. The observed full spreading rates are in the range 20-24 mm/yr, about 2-4 mm/yr faster than prevailing plate motion models predict. The two principal plates are separated by a 50-100 km wide deformation zone where strain accumulates. The velocity field is locally disturbed by tectonic and magmatic events. These include a persistent (1994-1998) intrusion episode in the Hengill volcanic system, an eruption in Grˇmsv”tn volcano in 1998, and an earthquake sequence in 2000 in the south Iceland seismic zone that contained two M_w 6.5 events and several events of M_{w≥5. The vertical deformation field shows high uplift rates, up to about 2 cm/yr, with maximum uplift occurring in central and central-east Iceland. Little deformation or subsidence is normally observed in coastal regions. The vertical deformation is influenced by a progressive reduction of ice mass at the ice caps in central Iceland; this reduction began in 1890 due to climatic change.}
DE: 1209 Tectonic deformation (6924)
DE: 1621 Cryospheric change (0776)
DE: 8158 Plate motions: present and recent (3040)
DE: 8416 Mid-oceanic ridge processes (1032, 3614)
SC: Geodesy [G]
MN: Fall Meeting 2005