Jökull - 01.01.2010, Side 17

Fifteen years of CGPS in Iceland
activity in the region increased substantially. Prelimi-
nary analysis of InSAR and campaign GPS data show
uplift with a maximum of 2–3 cm/yr during 2007–
2009, centered southwest of Lake Kleifarvatn and
north of the CGPS station KRIV (Judicael Decriem,
personal communication, 2009). The station showed
subsidence at similar rates between September 2009
and April 2010 when uplift started again. The activity
suggests pressure changes related to a magma source
at shallow depth and/or a natural pressure increase in
the high-temperature geothermal system in Krísuvík
followed by a pressure release.
Figure 8. Time series of detrended motion CGPS stations in SW Iceland. Map on lower right shows station
locations. Here the mean velocity and offsets have been removed from the time series. Vertical lines note
times of the 2000 and 2008 earthquakes. The original time series were processed using Bernese versions 5.0
and 4.2. Data before 2007 was processed with Bernese 4.2 with final orbits from CODE, relative to REYK
as described by Geirsson et al. (2006). Data after 2007 was processed with Bernese 5.0 using predicted or-
bits from CODE tied to the ITRF2000 using fiducial stations in Europe and North Amercia. Data points with
five times the median uncertainty have been rejected. Post-2007 data are shown relative to REYK for compli-
ance. The sites are mostly affected by post-seismic deformation after the 2008 earthquake and a gradual change
in velocities at some sites (e.g. HLID and OLKE). Site KRIV shows signals in the north component from a
nearby inflation/deflation episode. Kl: Lake Kleifarvatn. – Tímaraðir samfelldra GPS stöðva á Suðvesturlandi
eftir að meðalhraði hverrar stöðvar og stökk í tímaröðunum hafa verið dregin frá upprunalegu tímaröðinni.
Frávik stöðvanna frá flatri línu eru yfirleitt vegna hreyfinga eftir jarðskjálftana 2008 eða vegna tímaháðra
hraðabreytinga (t.d. HLID og OLKE). KRIV sýnir merki frá landrisi og -sigi skammt norðan stöðvarinnar.
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