Geological Survey of Finland, Special Paper 46 - arkisto.gsf.fi

Postglacial fault alignment
The orientation of the AP-interpreted fault lines
(tentatively PGFs) in Utsjoki (Figs. 1-2) was inconsistent
with the predominant southwest-northeast
pattern found in Kittilä and elsewhere in northern
Fennoscandia, but is rather similar in orientation
to those (NW-SE) reported from Kalastajasaarento
(Rybachi Peninsula) (Tanner 1930) and those in the
Kola Peninsula (Roberts et al. 1997). On the basis
of a higher block in the down-ice direction, one may
consider the northwest-southeast pattern of the PGFs
to coincide with the retreat pattern of the margin of
FIS after the YDEMs (see Norkalott Project 1987).
The major PGFs recognized in northern Fennoscandia,
however, are trending southwest to northeast;
including the Suasselkä-Homevaara fault in Finland
(Kujansuu 1964, Sutinen 2005), the Pärvie fault in
Sweden (Lundqvist & Lagerbäck 1976, Lagerbäck
1979) as well as the Stuorragurra fault in Norway
(Dehls et al. 2000; Fig. 1). Such orientation seems
not to directly coincide with the retreat pattern of
the FIS.
Geological Survey of Finland, Special Paper 46
Time-transgressive evolution of landslides possibly induced by seismotectonic events in Lapland
RESULTS AND DISCUSSION
Morphology
We found more than 30 paleolandslides/landslide
scars in the Utsjoki area (Figs. 1-5). The slides were
found at altitudes of 405-360 m (a.s.l.), demonstrating
that the valley fl oors were still ice-covered at
the time of slides (Figs. 2 and 5). This is particularly
well demonstrated in the case of the Lake Fanasjavri
paleoslides at altitudes of 400-360 m a.s.l.,
but with no signs of sediment disturbances on the
valley fl oor at an altitude of approximately 300
m a.s.l. (Fig. 5). The slide features on the Stuorra
Gallovarri fell were distributed on all expositions of
the fell slopes (Fig. 2), but some slides were found
even in moderately fl at surfaces. The length of
the slides varied from 0.9 to 1.2 km, width from
0.3-0.5 km, and slope from 3.5 to 7.8%, respectively.
The initiation of the slides had occurred at
390-405 m a.s.l. Bare rock and/or large boulders
were often on the fl oors of the slide scars (Fig 3-
4), demonstrating that soil moisture saturation had
preceded the slide events (Sutinen 1992, 2005, Hänninen
& Sutinen 1994).
Fig. 7. Outlook of small paleolandslide ridge (foreground/ clearcut; location shown by arrow for sites 4-11) and 15m high ridge
(upper right-hand corner/ Norway spruce-downy birch-aspen-forest) in Rietsamo, Kittilä.
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