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Geodetic GPS Measurement in South Iceland: Strain accumulation and partitioning in a propagating ridge system

LaFemina, P. C., T. H. Dixon, R. Malservisi, T. Árnadóttir, E. Sturkell, F. Sigmundsson, and P. Einarsson (2005), Geodetic GPS Measurement in South Iceland: Strain accumulation and partitioning in a propagating ridge system, J. Geophys. Res., 110, B11405, doi:10.1029/2005JB003675.

Abstract
GPS observations in south Iceland between 1994 and 2003 are compared with two-dimensional elastic half-space and viscoelastic
coupling models for two parallel rift zones, representing the Western and Eastern volcanic zones (WVZ, EVZ). GPS data from
the Hreppar block, between the WVZ and EVZ, fit a rigid block model within uncertainties. Spreading rates across the WVZ increase
from 2.6 ± 0.9 mm/yr in the northeast to 7.0 ± 0.4 mm/yr in the southwest. Conversely, spreading rates in the EVZ decrease
from 19.0 ± 2.0 mm/yr in the northeast to 11.0 ± 0.8 mm/yr in the southwest, the direction of ridge propagation. Summed extension
rates across the two rift zones are approximately constant and equal to the total plate rate, ∼18–20 mm/yr, consistent with
a simple propagating ridge model whereby the WVZ is deactivating in the direction of EVZ propagation. The coupling model confirms
results from the simple elastic half-space model, including relatively shallow locking depths (<5 km) beneath the rift zones,
and allows for an estimate of mean viscosity (∼1019–1020 Pa s) beneath the elastic layer. The location of maximum surface velocity gradient in the EVZ, presumably the locus of subsurface
magma accumulation and future rifting, does not coincide with the 1783–1784 Lakagígar fissure eruption but is 20 km to the
west, on the Bárðabunga-Veidivötn fissure swarm. This had a small volume eruption in 1862–1864 but a major eruption in 1477
A.D.
Further information
BibTeX
@article{id68,
  author = {P. C. LaFemina and T. H.  Dixon and R. Malservisi and T. {\'A}rnad{\'o}ttir and E. Sturkell and F. Sigmundsson and P. Einarsson},
  journal = {J. Geophys. Res.},
  title = {{Geodetic GPS Measurement in South Iceland: Strain accumulation and partitioning in a propagating ridge system}},
  volume = {110},
  year = {2005},
  language = {en},
  url = {http://venus.geophysik.uni-muenchen.de/~malservisi/papers/Lafeminaetal{\_}Iceland{\_}2005.pdf},
  doi = {10.1029/2005JB003675},
  eid = {B11405},
}
EndNote
%0 Journal Article
%A LaFemina, P. C.
%A Dixon, T. H. 
%A Malservisi, R.
%A Árnadóttir, T.
%A Sturkell, E.
%A Sigmundsson, F.
%A Einarsson, P.
%D 2005
%V 110
%J J. Geophys. Res.
%T Geodetic GPS Measurement in South Iceland: Strain accumulation and partitioning in a propagating ridge system
%U http://venus.geophysik.uni-muenchen.de/~malservisi/papers/Lafeminaetal_Iceland_2005.pdf
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Printed 08. Aug 2020 08:47