Jökull - 01.01.2004, Blaðsíða 68

Guðmundsson et al.
Figure 2. Earthquake epicenters (red dots) recorded in the year 2003 by the SIL seismic system. The main
tectonic features of Iceland are shown. RR denotes the Reykjanes Ridge, SISZ the South Iceland Seismic
Zone, EVZ the Eastern Volcanic Zone, WVZ the Western Volcanic Zone, TFZ the Tjörnes Fracture Zone, V
the Vatnajökull Ice Cap and M the Mýrdalsjökull glacier – Kort sem sýnir jarðskjálfta (rauðir punktar) sem
staðsettir voru með SIL kerfinu árið 2003.
The seismic activity in the South Iceland seismic
zone (SISZ) was mainly concentrated on the faults of
the June 2000 main shocks. The number of these af-
tershocks is decreasing and most of them cluster close
to the origin of the main shocks.
The Tjörnes Fracture Zone had several earthquake
swarms. Earthquake swarm activity occurred north
and east of Grímsey in June, August and October. The
biggest earthquake in these swarms, with magnitude
Mlw = 3.7, occurred 18 km north of Grímsey on Oc-
tober 15. There was also swarm activity in the mouth
of Eyjafjörður and in Öxarfjörður.
68 JÖKULL No. 54, 2004