Jökull - 01.01.2013, Side 106

F. Fuchs et al.
10 km
Figure 1. Map of the Snæfellsnes peninsula showing the Snæfellsjökull, Lýsuhóll, and Ljósufjöll volcanic cen-
ters (triangles) as well as the orientation of geological lineaments described by Sigurdsson (1970) (dashed
lines). The shaded regions mark distributions of volcanic systems in the region. The location of the inferred
transcurrent fault is indicated by the east-west trending solid line. The positions of our seismic stations are
denoted by squares. – Kort sem sýnir eldstöðvakerfin á Snæfellsnesi, sem kennd eru við Snæfellsjökul, Lýsuhól
og Ljósufjöll (þríhyrningar og punktalínur), sem og línur gegnum gýgaraðir, sem Haraldur Sigurðsson lýsir í
grein sinni frá 1970 (strikalínur). Staðsetning austur-vestur brotalínu, sem nefnd er í sömu grein er sýnd með
heilli línu. Staðsetning jarðskjálftastöðvanna er gefin með ferningum.
ther east is the Lýsuhóll (or Helgrindur) volcanic sys-
tem which was active during the Holocene while the
Ljósufjöll volcanic system marks the easternmost ex-
tension of the SVB. Here the 1050 BP Rauðhálsar
event took place, which is the most recent volcanic
eruption in the SVB (Flude et al., 2008; Jóhannes-
son, 1982a). However, the reason why the Snæfells-
nes peninsula features rejuvenated volcanism with the
observed alignment remains unknown.
Geophysical data in the region are sparse when
compared to geological and geochemical data. Little
is known about the deep structure of the Snæfellsnes
peninsula. Based on recordings from the HOTSPOT
experiment both Allen et al. (2002) and Du et al.
(2002) report a crustal thickness of about 15–20 km
for the Snæfellsnes, which is the thinnest crust on Ice-
land. Darbyshire et al. (2000) estimated the Moho
depth underneath the Snæfellsnes to 20–24 km. There
is no record of historic seismicity on the Snæfellsnes.
Also, no data are available about present day seismic-
ity in this part of Iceland because the South Iceland
Lowland (SIL) network is not designed to detect "low-
magnitude events" occurring beneath the Snæfellsnes
peninsula. Only during the HOTSPOT experiment in
1996–1998 a seismometer was placed near Snæfells-
jökull. Therefore, we performed a seismic campaign
to determine whether any seismicity occurs in this re-
gion near the volcanic centers.
Seismicity has previously been reported from
many other central volcanoes on Iceland, e.g. Askja
(Soosalu et al., 2009) and Eyjafjallajökull (Tarase-
wicz et al., 2012) and also from long-dormant vol-
106 JÖKULL No. 63, 2013