Introduction
The term karst breakdown is used in this paper to de-
note the totality of processes and phenomena of gravi-
tational and/or hydrodynamic destruction of the ceiling
of a karst cavity and of the overlying sediments. Use of
this more general concept avoids potential misconcep-
tions that commonly arise from the ambiguous use of
A. Klimchouk
V. Andrejchuk
Karst breakdown mechanisms
from observations in the gypsum
caves of the Western Ukraine:
implications for subsidence hazard
assessment
Received: 9 March 2002
Accepted: 1 March 2005
Published online: 11 May 2005
Ó Springer-Verlag 2005
Abstract The term karst breakdown
is employed in this paper to denote
the totality of processes and phe-
nomena of gravitational and/or
hydrodynamic destruction of the
ceiling of a karst cavity and of the
overlying sediments. It refers not
only to the existence of a surface
subsidence (collapse) feature but,
first of all, to the ‘‘internal’’ (hidden
in the subsurface) structures that
precede development of a surface
form. This study reports and dis-
cusses the results of direct mapping
and examination of breakdown
structures in the gypsum karst of the
Western Ukraine, at the level of
their origin, i.e., in caves. The
accessibility of numerous laterally
extensive maze cave systems in the
region provided an excellent oppor-
tunity for such an approach, which
made it possible to examine the
relationship between breakdown
structures and particular morpho-
genetic or geological features in
caves, and to reveal stages of
breakdown development. It is found
that breakdown is initiated mainly at
specific speleogenetically or geologi-
cally ‘‘weakened’’ localities, which
classify into a few distinct types. The
majority of breakdowns, which are
potent to propagate through the
overburden, relate with the outlet
cupolas/domepits that represent
places where water had discharged
out of a cave to the upper aquifer
during the period of transverse
artesian speleogenesis. Distribution
of breakdown structures does not
correlate particularly well with the
size of the master passages. Several
distinct mechanisms of breakdown
development are revealed, and most
of them proceed in several stages.
They are guided by speleogenetic,
geological and hydrogeological fac-
tors. The study confirms that a spe-
leogenetic approach is indispensable
to the understanding of breakdown
pre-requisites and mechanisms, as
well as for eventual subsidence haz-
ard assessment. Direct observations
in caves, aimed both at speleogenetic
investigation and breakdown char-
acterization on regional- or site-
specific levels, should be employed
wherever possible.
Keywords Karst subsidence Æ Karst
breakdown mechanisms Æ Gypsum
caves Æ Speleogenesis Æ Subsidence
hazard assessment
Environ Geol (2005) 48: 336–359
DOI 10.1007/s00254-005-1279-1
ORIGINAL ARTICLE
A. Klimchouk (&)
Institute of Geological Sciences, National
Academy of Sciences of Ukraine,
P.O.Box 136, 01030 Kiev, Ukraine
E-mail: klim@speleogenesis.info
V. Andrejchuk
Department of Earth Science,
Silesian University, Sosnovec, Poland