HR: 0800h
AN: G51A-0055    [Abstracts]
TI: Magma dynamics and volcano geodesy in Iceland
AU: * Sturkell, E
EM: erik@vedur.is
AF: Icelandic Meteorological Office, Bustadavegur 9, Reykjavik, 150 Iceland
AU: Einarsson, P
EM: palli@raunvis.hi.is
AF: Earth Science Institute, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Sigmundsson, F
EM: fs@hi.is
AF: Nordic Volcanological Center, Earth Science Institute, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Roberts, M J
EM: matthew@vedur.is
AF: Icelandic Meteorological Office, Bustadavegur 9, Reykjavik, 150 Iceland
AU: Geirsson, H
EM: dori@vedur.is
AF: Icelandic Meteorological Office, Bustadavegur 9, Reykjavik, 150 Iceland
AU: Olafsson, H
EM: hallo@hi.is
AF: Nordic Volcanological Center, Earth Science Institute, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: Pedersen, R
EM: rikke@hi.is
AF: Nordic Volcanological Center, Earth Science Institute, University of Iceland, Sturlugata 7, Reykjavik, 101 Iceland
AU: de Zeeuw-van Dalfsen, E
EM: E.Van.Dalfsen@open.ac.uk
AF: Volcano Dynamics Group, Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA United Kingdom
AU: Linde, A T
EM: alinde@dtm.ciw.edu
AF: Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, N.W. Washington, DC 20015 United States
AU: Sacks, S I
EM: sacks@dtm.ciw.edu
AF: Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, N.W. Washington, DC 20015 United States
AU: Stefansson, R
EM: ragnar@vedur.is
AF: Icelandic Meteorological Office, Bustadavegur 9, Reykjavik, 150 Iceland
AB: Here we review the achievements of volcano geodesy in Iceland during the last 15 years. Extensive measurements of crustal deformation have been conducted using a variety of geodetic techniques, including levelling, electronic distance measurements, campaign and continuous GPS geodesy, and interferometric analysis of synthetic aperture radar images (InSAR). Results from these measurements provide a comprehensive view of the behavior of Icelandic volcanoes. Between inflation, intrusion, and eruption episodes, volcanoes are likely to deflate or show no sign of seismic activity. Subsidence rates are often in the range of a few millimeters to a few centimeters a year, reducing progressively with time since the last eruption or intrusion at the volcano. Subsidence can be caused by cooling and contraction of magma, outflow of magma, or it can related to plate spreading.Volcano subsidence or lack of deformation is often interrupted by episodic magma flow towards near-surface locations. Such magma recharge has been observed geodetically at Hengill, Hekla, Eyjafjallajokull, Katla, Grimsvotn, and Krafla volcanoes, with inflow inferred to last from a few months up to two decades. In the last 15 years, four volcanic eruptions, three intrusive events and two $>$M6 earthquakes have occurred. In recent years, the Grimsvotn and Katla volcanoes have exhibited inflation at a rate of 1-2 cm per year, while the Hekla and Torfajokull volcanoes have inflated at rates an order-of-magnitude less. Subsidence is occurring presently at the Askja and Krafla volcanoes. Within the period of geodetic measurement, signals consistent with no deformation are typical for most of the 35 active volcanoes in Iceland.
DE: 1206 Crustal movements--interplate (8155)
DE: 1208 Crustal movements--intraplate (8110)
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting