Geoscience Reference
In-Depth Information
3
Recent Geodynamics and Karst
are investigated by Garasic (
1981
) and Garasic and
Cvijanovic (
1985
).
During the 1970s, similar observations in the karst
regions of Crimea were made by Dublyansky and
Molodih (
1972
). Professor Dublyansky distinguishes
five groups of karst features bearing seismotectonic
information: displaced cave galleries, moved lime-
stone blocks, corrosion-gravitational forms (caves and
pot-holes of tectonic origin), cave breakdowns, and
speleothems (Dublyansky
1995
).
Moser and Geyer accepted the presence of
deformed speleothems in caves in the Bavarian Upper
Franconia region, Germany, as a result of strong
earthquakes (Moser and Geyer
1979
).
The paleoseismologic research in karst became
more popular in Europe after a number of studies of
caves in Italy were carried out in the 1980s by the
team of Prof. Paolo Forti at the University of Bologna
(Forti
1997
,
1998
; Forti and Postpischl
1981a
,
b
,
1984
,
1985
,
1986
,
1987
; Forti et al.
1983
; Postpischl
et al.
1990
,
1991
).
Undoubtedly, it is almost impossible within the
frames of this topic to examine in detail all studies
conducted till date. In this chapter, we try to provide a
brief overview of the paleoseismologic and active
tectonics research carried out so far in caves from
different karst regions of the world.
Belgium is characterized by relatively low con-
temporary seismic activity. The strongest historical
earthquake was in September 18, 1692 in Verviers,
Northern Ardennes (Camelbeeck
1998
). However,
several trench studies along the active Bree fault in
northern Belgium (Vanneste et al.
2001
) were per-
formed obtaining further evidence for three strong
3.1
Traces of Paleoseismicity
and Active Tectonics in Karst:
Historical Notes
The first to discuss damages of speleothems in caves
as a result of tectonic events (earthquakes) was
Hohenwart (
1832
) in his observations of Postojna
Cave in the first half of nineteenth century. According
to the translation of Kempe (
2004
), Graf von
Hohenwart wrote in his guide of the cave: ''Also the
forceful changes in the grotto show that nature rules
after own law -unknown to us—in this netherworld.
The common opinion about these alterations in
such underground caves is that weak vaults cavein
due to earthquakes and that loose stems fall from
above and that those stalactite columns which do not
adhere strongly enough at their junction to the ceiling
are precipitated. The careful observer, however, dis-
covers that many alterations cannot be explained by
this common opinion.'' (Kempe
2004
, p. 272).
The hypothesis that speleothems can ''record''
seismotectonic history is mentioned in the studies of
Becker on the caves Bing Hohle in Germany and
Han-sur-Lesse, Belgium (Becker
1929
). Damages of
speleothems are also reported by Spöcker in Franken
Jura but without assumption for their seismic nature
(Spöcker
1933
).
Later, Schillat established an availability of broken
speleothems in Langenfeld Cave and discussed the
seismic origin of the deformations (Schillat
1965
,
1970
). Systematic studies on deformed stalagmites in
Postojna Cave are published by Gospodarich (
1968
,
1977
,
1981
). Speleological phenomena with possible
tectonic origin in karst areas of the Dinaric Mountains
