Jökull - 01.01.2010, Page 5

Fifteen years of CGPS in Iceland
Figure 1. A map of Iceland showing CGPS station locations, observed horizontal velocities relative to stable
North America, and main tectonic and volcanic features in Iceland. The stations are divided into sub-networks
by different symbols and colors. The velocity field is calculated from daily station observations from when the
station was installed until the end of 2009, using the GAMIT/GLOBK software as described by Hreinsdottir
et al. (2009). Black arrows show predicted site velocities from the MORVEL plate motion model (DeMets et
al., 2010). Error ellipses note 2-sigma uncertainties. The yellow areas show individual fissure swarms associ-
ated with central volcanoes (black circles) (Einarsson and Sæmundsson, 1987). Blue N-S striking lines in the
SISZ show locations of the 2000 and 2008 earthquake sequence main faults (right two lines and left two lines,
respectively). Site ISAF has too short time series to allow meaningful estimates of the velocities, and GFUM
is much affected by the recent eruption and ongoing inflation. Sections of the plate boundary are abbreviated
in gray: Rp: Reykjanes peninsula; WVZ, EVZ, and NVZ: Western, Eastern, and Northern Volcanic Zones,
respectively; SISZ: South Iceland Seismic Zone; Hb: Hreppar block; CIVZ: Central Icelandic Volcanic Zone;
KR: Kolbeinsey Ridge; GOR: Grímsey Oblique Rift; HFF: Húsavík-Flatey Fault; DZ: Dalvík Zone. GOR,
HFF, and DZ comprise the Tjörnes Fracture Zone. White areas denote ice-caps, selected volcanic systems
are abbreviated by: Kr: Krísuvík; He: Hengill; H: Hekla; E: Eyjafjallajökull; Ka: Katla; O: Öræfajökull; G:
Grímsvötn; A: Askja; U/A: Upptyppingar-Álftadalsdyngja. – Kort af færsluhröðum samfelldra GPS stöðva
miðað við fastan Norður Ameríkufleka. Færslur eru reiknaðar frá upphafi mælinga á hverri stöð til loka árs
2009. Til samanburðar er sýndur áætlaður hraði þriggja stöðva samkvæmt líkani af plötuhreyfingum (DeMets
et al., 2010).
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