GEOLOGICA CARPATHICA, 49, 4, BRATISLAVA, AUGUST 1998
SEISMOGENIC ZONES IN THE EASTERN ALPINE-WESTERN
CARPATHIAN-PANNONIAN JUNCTION AREA
, MICHAL KOVÁÈ
, DUAN PLAIENKA
and MARTIN UJAN
Department of Applied and Environmental Geophysics, Faculty of Science, Comenius University,
Mlynská dolina, 842 15 Bratislava, Slovak Republic
Department of Geology and Paleontology, Faculty of Science, Comenius University, Mlynská dolina, 842 15 Bratislava, Slovak Republic
Geological Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 842 26 Bratislava, Slovak Republic
EQUIS Ltd., Raèianska 57, 831 02 Bratislava, Slovak Republic
(Manuscript received October 14, 1997; accepted in revised form June 16, 1998)
Abstract: The newly-defined seismogenic zones in the Alpine-Carpathian-Pannonian (ALCAPA) junction area are
correlated with: (1) Paleoalpine deep-seated suture zones, either oceanic or intracontinental, (2) Neoalpine wrench-
fault zones following some sutures, and (3) original thrust planes reactivated as low-angle extensional normal faults.
1The principal West-Carpathian Paleoalpine sutures, from north to south, are: the Penninic-Vahic oceanic suture
originated during the Late Cretaceous, the Èertovica intracontinental suture between the Tatric and Veporic thick-
skinned sheets locked some 90 Ma ago, and the Meliatic oceanic suture formed in the Late Jurassic, closely related to
the Igal-Bükk Zone. These suture zones were partly reactivated during the Late Tertiary and represent weakened
zones in the modern upper crust. The concentration of important earthquake epicenters correlates well with these
weakened belts which serves as a base for the new seismogenic model of the area. 2The most important wrench
fault zone is situated between the Eastern Alps and Western Carpathians. It reflects the Miocene extrusion of the
ALCAPA lithospheric fragment from the Alpine domain as its northwestern boundary. The NESW trending wrench
fault zone is represented by the Mur-Mürz-Leitha and Povaie fault systems. The zone is well expressed by flower
structures in many seismic lines. 3The Miocene back-arc extension driven by the subduction pull in front of the
Carpathian orogen and mantle updoming in the Pannonian domain reactivated original Paleoalpine thrusts as crustal
detachment planes. In the Danube Basin area, these are accompanied by numerous important faults visible in seismic
sections, e.g. the Répce, Rába, Sládkovièovo and Mojmírovce fault systems. The extension regime consequences of the
core-mountains uplift during isostatic inversion from the Pliocene are visible in seismic section 2T along the Èertovica
Zone as strong reflector branches. They represent former suture rejuvenated into younger low angle normal faults.
Key words: ALCAPA region, suture zones reactivation, rheology, earthquake distribution, seismogenic model.
Seismogenic zones, i.e. zones with increased seismic risk in
the Western Carpathians and surrounding areas were derived
from geophysically interpreted deep fault zones in the past
(Figs. 2 and 3). These were defined by Fusán et al. (1979,
1981, 1987) and efara et al. (1987), following the division of
the Western Carpathians into neo-tectonic blocks (Fig. 1).
This pioneer step in the definition of the neo-tectonic evolu-
tion of the Western Carpathians was based on the contempo-
rary knowledge of deep-seated structures supported by refrac-
tion seismic lines (DSS) and gravimetry. Moreover, this
concept was consistent with the geodetic data on recent verti-
cal movements. It is necessary to emphasize that the above
mentioned deep fault zones (Figs. 1, 2, 3) have been used to
define the seismogenic zones by seismologists (e.g. Schenk et
al. 1986; teinberg et al. 1988; imùnek et al. 1991) without
(or only with partial) analysis of the seismic event generation
(e.g. Pospíil et al. 1985).
The geophysical and geological research in the last decade
has brought more exact data which are not consistent with all
the originally interpreted deep-seated zones, or they define
more precisely their character at depth. The most important of
these new data include reflection seismic lines (CDP Tomek
et al. 1989; Tomek & Hall 1993 etc.), magnetotelluric sounding
(MTS e.g. Varga & Lada 1988) and some other results of
complex geophysical and geological interpretation (e.g. efara
et al. 1996). These new results serve as a basis for the new
model of seismogenic zones in the Alpine-Carpathian-Pannon-
ian (ALCAPA) junction area presented in this paper.
The previous model of the neo-tectonic block
structure of the Western Carpathians
and its relationship to deep-seated faults
The principal neo-tectonic blocks of the Central and Inner
Western Carpathians, as defined by Fusán et al. (1981), are the
Outer Carpathian blocks, the Danube block, the Fatra-Tatra
block, the Rudohorie-Pilis block and the Potisie block (Fig. 1).
Except for the Potisie block, all the mentioned blocks are repre-
sented in the area considered in the present paper.
The principal Outer Carpathians blocks (Fig. 1) consist
of two parts. The lower part is formed by platform elements
partly underthrusting the Central Carpathians; the upper part
consists mainly of the flysch nappes of the Outer Car-
248 EFARA, KOVÁÈ, PLAIENKA and UJAN
pathians. In the Slovak-Moravian block, the Mesozoic com-
plexes and the thick Miocene cover are present in the Vien-
na Basin substratum besides the flysch nappes. An impor-
tant geoelectric anomaly (MTS, MVS) follows the boundary
between the Central and Outer Western Carpathians
(Pìèová et al. 1976; Èerv et al. 1994).
The Danube block was geologically characterized by the
presence of thick sedimentary cover and subsidence of up to
3 mm/y in the Danube Basin area. The NW block margin can
be partly correlated with the peri-Carpathian lineament which
continues along the Pieniny Klippen Belt and follows the su-
ture zone between the Outer and Central Western Car-
pathians. The originally defined SW continuation of the
northern margin of the Danube block (Fusán et al. 1979,
1981, 1987), which passes through the Sopron and Kõszeg
areas, was originally determined as a boundary between thick
Alpine and thinned Danube Basin crust. From the present
point of view, the principal boundary is more likely a deep-
seated structure, reflected on the surface as the Mur-Mürz-
Leitha seismically active tectonic line, connected with the
The northeast boundary of the Danube block with the
Fatra-Tatra block trends in the NWSE direction. This
boundary, surficially defined as the Pøerov-tiavnica fault
(Fusán et al. 1981) is geologically very heterogeneous and
its activity during the Neoalpine evolution is doubtful. Simi-
larly questionable is the activity of the NW-SE oriented
faults that occur in the pre-Tertiary basement of the Danube
Basin. Among these are the Dobrá Voda fault zone defining
the southern margin of the Povaský Inovec Mts. and the
Tribeè Mts., continuing further to Nové Zámky and túrovo,
and two other faults running parallel to this line in the basin
basement: one running from Pezinok to Komárno and the
second one along the Danube River (Fusán et al. 1981, cf.
Figs. 1, 2). From the viewpoint of present knowledge, these
should be regarded only as relics of the pre-Neogene tecton-
ics, because they are absent in the sedimentary infill of the
basin, as it is well documented by many seismic profiles
through the area (e.g. Hruecký et al. 1996).
The present-day views on the geometry of the Moho dis-
continuity are also different from those proposed by Fusán et
al. (1981) for the model of the West-Carpathian block struc-
ture. For instance, the current opinion is that an elevated
neo-Moho in the western part of the Inner Western Car-
pathians continues as far as the peri-Klippen Belt zone, i.e. it
crosses the boundary between the Danube and Fatra-Tatra
blocks (Fig. 4).
On the basis of these facts, the so-called Pøerov-tiavnica
deep-seated zone and the more southern zones with the same
NWSE trend (e.g. the Dobrá Voda or Pezinok-Komárno
fault zones), which were defined mainly on the basis of the
original Moho image in this area, are no longer believed to
play any important role in Late Tertiary tectonics of the
Fig. 1. Neo-tectonic blocks of the Western Carpathians (Fusán et al. 1981). Legende: 1 Pieniny Klippen Belt, 2 deep seated block
boundaries, 3 Moho discontinuity contours depth in km, Neo-tectonic blocks: I. Danube block, II. Rudohorie-Pilis block, III. Potisie
block, IV. Fatra-Tatra block, V.,VI., VII. and VIII. Outer Carpathian blocks.
SEISMOGENIC ZONES IN THE EASTERN ALPINE-WESTERN CARPATHIAN-PANNONIAN JUNCTION AREA 249
The Fatra-Tatra block is characterized by morphological
elevations of the core-mountains and depressions filled by
Paleogene and Neogene sediments. The block has an uplift-
ing tendency at a rate of over 2 mm/y. Its northern boundary
is represented by the Pieniny Klippen Belt (Figs. 1, 2). In
this block, besides the faults defining the core-mountains,
the Central Slovak fault system which reaches the lower
crustal parts plays a principal role (Fusán et al. 1987; Kováè
& Hók 1993). This fault system forms a wide N-S directed
fault zone, narrowing downwards, running from the
Turèianska kotlina Depression through the iarska kotlina
Depression and further southwards along the Hron river val-
ley (Figs. 2, 3).
The NE trending boundary of the Rudohorie-Pilis block
with the Danube and Fatra-Tatra blocks was defined by a
density inhomogeneity along the Komárno-Poprad Line (the
Vepor deep-seated fault of Fusán et al. 1979), continuing to
the Outer Carpathians territories (Fig. 1). In a broader sense
this boundary can be correlated with the contact between the
Tatric and Veporic basement units, known as the Èertovica
Line on the surface.
Only negligible vertical movements were recorded in the
Rudohorie-Pilis block, hence this area was considered to be
relatively stable (Fusán et al. 1987). However, this is not
consistent with the seismic activity probably along the Èer-
tovica Line zone (earthquakes in the Banská Bystrica area)
and the Hurbanovo-Diósjenõ fault system (earthquakes in
the Komárno area).
The Potisie block has very indistinct boundaries (Fusán et
al. 1987). In the east, it is formed by a NS trending fault-
system in the area of the Slanské vrchy Mts.; in the north-
east it is represented by the Pieniny Klippen Belt (Fig. 1).
Fig. 2. Zones of possible earthquake generation after imùnek et al. 1991.
250 EFARA, KOVÁÈ, PLAIENKA and UJAN
The block is characterized by a thick Neogene sedimentary
cover and subsidence rate of up to 2 mm/y.
Depth and distribution of earthquakes
and crustal rheology
Earthquakes deeper than 2030 km are known only along
the front of the Carpathians and/or along the southeastern
margin of the Pannonian Basin (Procházková et al. 1994; La-
bák & Brouèek 1996). The only Benioff Zone in the Car-
pathian arc related to the subduction process is situated in the
Vrancea region, where earthquakes occur at depths of 10180
km (Fuchs et al. 1979). All other earthquakes are shallow and
their origin is related to different processes than subduction.
A notable West-Carpathian exception is the Kremnica region
located within the NS trending Central Slovak fault zone.
Here earthquakes as deep as 30 km have been assumed to oc-
cur but by latest the analyses (Labák 1996; Labák et al. 1996)
this depth of foci has no real evidence. Elsewhere in the Slo-
vak territory earthquakes generally originate at depths shal-
lower than 1517 km. This fact can be well correlated with
Fig. 3. Zones of possible earthquake generation after teinberg et al. 1988.
SEISMOGENIC ZONES IN THE EASTERN ALPINE-WESTERN CARPATHIAN-PANNONIAN JUNCTION AREA 251
the maximum depth of the brittle crust which is the only zone
strong enough to accumulate enough potential strain energy
to produce destructive earthquakes.
The thickness of the brittle crust in the Western Car-
pathians was estimated by Bielik & Stríenec (1994) on the
basis of a crustal profile running from the Polish part of the
North European Platform to the Carpathians and Pannonian
Basin. The maximum estimated thickness along this profile
is about 35 km, with 25 km being the more common thick-
ness. However, the high heat flow, particularly in the north-
ern parts of the Pannonian Basin (Fig. 5), indicates an elas-
to-plastic behaviour of the crust even at depths less than
indicated along the above mentioned crustal profile.
According to the rheological model of Lankreijer et al.
(1998), the strong area of the Bohemian Massif rapidly loses
its strength towards the Carpathians. Nevertheless, the Car-
pathian foreland area is still relatively strong (Lankreijer 1998).
The Vienna Basin is also characterized by a remarkably strong
lithosphere. The Danube Basin, typically, only displays lithos-
pheric strength in the uppermost parts of the crust (Fig. 6). Be-
cause the substantial part of sedimentary filling also cannot be
considered as brittle (upper 39 km), only a very thin layer re-
mains for the potential generation of earthquakes. Actually, the
central part of the Danube Basin, except for a few small earth-
quakes on the Hungarian side, is generally aseismic.
The high heat flow and the related thinner brittle crust is
also observed in the northern continuation of the Danube Ba-
sin, as far as the Pieniny Klippen Belt. This fact is also sup-
ported by measured geothermal conditions in the Soblahov-1
borehole. All earthquakes recorded in this area are distributed
along the margin of this high heat flow zone (compare Figs. 5
A relatively shallow Moho, which is accompanied by an
increased heat-flow, is also known in some platform areas,
for example in the vicinity of Ostrava (Figs. 4 and 5), or fur-
ther west in the Ohøe rift (Fig. 6). This indicates that crustal
Fig. 4. Thickness of the Earth´s crust in the Carpathian-Pannonian area. Contours in km.
252 EFARA, KOVÁÈ, PLAIENKA and UJAN
Fig. 5. Heat-flow density map in the Carpathian-Pannonian area. Density contours in mWm
Fig. 6. Rheological NW-SE cross-section of Central Europe from the Bohemian Massif to the Danube Basin (Lankreijer et al. 1998). In-
terpreted strength contour plot (in MPa) for compressional deformation, at a strain-rate 10
SEISMOGENIC ZONES IN THE EASTERN ALPINE-WESTERN CARPATHIAN-PANNONIAN JUNCTION AREA 253
extension occurred during the Tertiary in foreland areas as
The newly defined seismogenic zones
of the ALCAPA junction area
The brittle part of the Earths crust is restricted to the upper
1535 km in the Western Carpathians. This zone contains
some inhomogeneities which originated during the geological
evolution of the Western Carpathians. Invoking the principle
of minimum energetic expenses, these less competent zones
are believed to be utilized as the primary source of the stress
release by faulting. These zones are represented by the origi-
nal Upper JurassicCretaceous intracontinental and oceanic
suture zones (1) which were often reactivated as fault zones
with various kinematics during the Late Tertiary and are still
potentially able to generate earthquake events. These reacti-
vated fault zones are mainly wrench fault corridors (2) re-
lated to the Miocene escape tectonics in the Carpathians and
the low-angle normal faults (3) occurring below the Neo-
gene basins which accommodated the upper crustal exten-
sion and/or isostatic uplift of the orogen.
(1) Principal suture zones of the Western Carpathians
The central and inner zones of the Western Carpathians are
marked by stacking of crustal imbricates that originated by
northward progradational shortening of heterogeneously
thinned epi-Variscan continental crust. Some of the zones at-
tenuated by Triassic-Jurassic rifting graded into domains
floored by oceanic crust which were sutured sequentially dur-
ing the Late Jurassic to Paleogene. Three types of crustal-
scale shortening zones were distinguished by Plaienka et al.
(1997): (A) original oceanic subduction zones which were
succeeded by collisional stacking of mobilized crust of conti-
nental margins, as the Meliatic and related sutures of the In-
ner Western Carpathians; (B) zones of continental and/or oce-
anic basement underthrusting and stacking within the crust,
characteristic for the Central Carpathians the intraconti-
nental Èertovica suture and originally oceanic Penninic-Va-
hic suture zone; (C) downbending of the rigid marginal fore-
land crust of the North European Platform, which was
overridden by the Tertiary accretionary wedge of the Outer
Identification of suture zones in the present structure of the
Western Carpathians is supported by seismic reflection pro-
filing and by magneto-telluric sounding (MTS), which show
the sutures as deep-seated low-resistivity zones. Particularly
the high conductivity of the latter zones indicates either ul-
tramylonites, or zones with deep-generated solutions, or oth-
er rock types containing clays and/or black shales. A meta-
morphic process with graphite coating on mineral grains also
cannot be ruled out. All these environments have a decreased
coefficient of friction, represent weakened or even discon-
tinuous zones within the crust and can potentially produce
In the area under consideration, the suture zones defined
by Plaienka et al. (1997) include both the oceanic and the
intracontinental shortening zones, which have recently acted
as weakened seismogenic belts. From north to south, the fol-
lowing zones are depicted (Fig. 7):
(A) The Penninic-Vahic suture zone which consumed
both the Vahic (i.e. South Penninic) oceanic and the Oravic
(i.e. Middle Penninic) continental crust. It originated during
the Late Cretaceous to Paleogene (7050 Ma) and it is
younger eastwards. In deep seismic sections, it is indicated
by flat reflectors in mid-crustal levels, which underlie the
Tatric thick-skinned crustal sheet (Tomek 1993; Vozár et al.
1995) and overlie the underthrust Oravic ribbon continent.
The zone is followed by an important Late Tertiary wrench
corridor continuing to the Pieniny Klippen Belt NE-ward
which controlled the eastward extrusion of the Western Car-
pathians and evolution of the Vienna Basin. This wrench
zone consists of several sections: the Mur-Mürz-Leitha fault
zone, the Dobrá Voda area (wrench zone and ENE-WSW
trending back-thrusts), and the Váh river valley as far as ili-
na (the peri-Carpathian lineament).
The Mur-Mürz-Leitha-ilina wrench corridor generates
earthquakes by movements of two kinematic types. The first
one is a horizontal displacement along a sinistral strike-slip
fault system accompanied by SWNE trending flower struc-
tures. The second type is contractional, related to older in-
herited ENEWSW trending structures (e.g. a wider zone
around Dobrá Voda and part of the Pieniny Klippen Belt
west of ilina).
(B) The Èertovica suture zone located between the Tat-
ric basement sheet and the Veporic crustal wedge is the
dominant feature of the deep seismic line 2T (Tomek et al.
1989; Tomek 1993) where it is indicated by a moderately
south-dipping stack of strong reflectors (Fig. 10). The zone
originated by the mid-Cretaceous shortening and under-
thrusting of a thinned continental crust of former Jurassic
Lower Cretaceous basinal area between the Tatric and Ve-
poric elevations. This attenuated, but buoyant crust
underplated the Veporic wedge and its sedimentary cover
was detached and transported northwards to create the
Krína cover nappe system overriding the Tatric Superunit.
The final locking of this zone occurred about 90 Ma ago
The zone comes to the surface in the area between the
towns of Banská Bystrica and Brezno and then obliquely
crosses the Nízke Tatry horst. It generates shallow earth-
quakes, released mostly on the ENE-trending Hron fault sys-
tem (Fig. 7), which is a superimposed Tertiary phenomenon.
It is noteworthy that this system, like the Dobrá Voda fault
system, can be clearly identified in the recent morphology
and can be easily traced by remote sensing methods (Jankù et
al. 1984). Earthquakes along the NS trending Central Slo-
vak fault system in the surroundings of the Turèianska kotli-
na Depression (with less data) can also be related to this
zone, along with its continuation to the Central Slovak neo-
(C) The Meliatic oceanic suture is closely related to the
Igal-Bükk Zone. Both were formed during the Late Jurassic
to the earliest Cretaceous (150120 Ma). The Meliatic su-
ture represents an original subduction zone evidenced by a
presence of dismembered ophiolite units, blueschists and
254 EFARA, KOVÁÈ, PLAIENKA and UJAN
Fig. 7. Principal West-Carpathian suture zones with respect to earthquake occurrences. Historical earthquake epicentres after Labák &
SEISMOGENIC ZONES IN THE EASTERN ALPINE-WESTERN CARPATHIAN-PANNONIAN JUNCTION AREA 255
coeval calc-alkaline volcanics. The Igal-Bükk Zone was
probably formed by closure of a small back-arc oceanic basin
(Szarvaskõ ophiolites), related to the southward subduction
of the Meliatic ocean. Both zones are rather steep (the former
south- and the latter north-dipping) to subvertical, but in the
western part, below the Neogene Danube Basin, the Meliatic
suture is probably flatter. In places, the Meliata suture can be
regarded as reactivated by low-angle normal faults (e.g. the
Rába Line Horváth 1993; Plaienka et al. 1997). Some
segments of the Igal-Bükk Zone were also reactivated as
wrench zones during the Late Tertiary (e.g. the Darnó Line).
The course of both zones is followed by earthquake epicen-
Fig. 8. Magnetotelluric (MTS) profiles in the Danube and Vienna Basins and their interpretation (Nemesi et al. 1997, modified). Important
zones of very low resistivity zones are related to: 1 basin filling, 2 Rába Line and its shallow depth continuation below the Transdanu-
bian Central Range, 3 Mur-Mürz-Leitha Line and its steep continuation at depth, 4 elevated resistivities.
Fig. 9. Seismic time cross-section along the 3T profile (Tomek & Thon 1988, modified). Flower structure in the Zohorsko-Plavecký gra-
ben, reflector packages F,G presents normal faults, MMoho, Hextension in lower crust. 1sinistral wrench.
256 EFARA, KOVÁÈ, PLAIENKA and UJAN
ters, especially in areas where they are followed by deep-
seated fault systems (Fig. 7).
In the area under consideration, the Meliata oceanic suture
is bound to the northwestern margin of the Transdanubian
Central Range, an element with comparatively thick crust in
the area. Stresses generated along this contact are released by
faults surficially represented by the WSW-ENE oriented
Hurbanovo-Diosjenõ fault zone. This fault system is related
to earthquake epicenters mainly at its crossing with smaller
transversel fault structures.
(2) Wrench fault zones
Deep-seated zones of very low resistivity have been identi-
fied by MTS method along a profile crossing the Vienna Ba-
sin, Malé Karpaty Mts. and the Danube Basin (Nemesi et al.
1997, cf. Fig. 8). One of these zones, shown as a flower-
structure in seismic lines, occurs in the vicinity of the Sch-
rattenberg fault on the western margin of the Vienna Basin
(Èerv et al. 1994). Another zone of very low resistivity was
identified in the SE part of the Vienna Basin (SE continua-
Fig. 10. Seismic time cross-section on the 2T profile (Tomek et al. 1989, modified).
Fig. 11. Interpretation of the magnetotelluric (MTS) measurements (modified after Varga & Lada 1988) along the 2T profile (see also Fig. 10).
SEISMOGENIC ZONES IN THE EASTERN ALPINE-WESTERN CARPATHIAN-PANNONIAN JUNCTION AREA 257
tion of the Malé Karpaty Mts. to Austria). Similar to the first
zone, this zone is represented by a seismically identified
flower-structure (Tomek & Thon 1988) close to the Malé
Karpaty Mts. (Fig. 9).
Based on the coincidence of the deep-seated low resistivity
zones and known faults, as well as on the knowledge about the
pull-apart opening of the Vienna Basin during the extrusion of
the West-Carpathian lithospheric fragment from the Alpine
collision zone in the early Miocene (Csontos et al. 1992;
Kováè et al. 1993), the low-resistivity zones can be reasonably
assumed to be first-order shear zones (Gutdeutsch & Aric
1988). This interpretation is consistent with the young Quater-
nary structure of the Zohorsko-Plavecký graben which is well
documented from the Neogene up to the Quaternary strata.
(3) Extension along the orogenic sutures
The Central Slovak area (the upper part of the Hron river
valley), where earthquakes occur more frequently than in
other parts of Slovakia is close to the Tatric-Veporic suture
Fig. 12. Seismo-geological domains of the Alpine-Carpathian-Pannonian junction area.
258 EFARA, KOVÁÈ, PLAIENKA and UJAN
zone. Along the 2T seismic profile (Fig. 10), besides the ob-
vious density of SE-inclined reflection boundaries (Tomek et
al. 1989) there are some zones of very low resistivity, which
are observable in the deeper zones (Fig. 11). The high densi-
ty of reflections may correspond to a probable extensional re-
activation of the Èertovica suture, along which earthquakes
The entire tectonic body of the Transdanubian Central
Range is underlain by zones of very low resistivity at 5 to
20 km depths (Nemesi et al. 1997, cf. Fig. 8). This would
imply that they represent originally incompetent sutures and
that the Transdanubian Range evidently represents an upper
unit (a crustal slice) whose movement along these sutures
was probably enabled by a low coefficient of friction of the
underlying masses (Tari 1996). The stress generated by this
movement is believed to be the primary source of earth-
quakes released on the brittle fault structures in this region
e.g. the N-S running transversal Mór graben (Figs. 12, 13).
Seismogenic zones discussion and conclusions
The rheological aspects of the brittle crust within the East Al-
pine-Western Carpathian-Pannonian junction, as well as the
presence of deep-seated faults, have been taken into account in
construction of a model of seismo-geological domains in this
Fig. 13. Seismogenic zones of the Alpine-Carpathian-Pannonian junction area. Historical earthquake epicentres after Labák & Brouèek 1996.
SEISMOGENIC ZONES IN THE EASTERN ALPINE-WESTERN CARPATHIAN-PANNONIAN JUNCTION AREA 259
area (Fig. 12). Several domains are identified: the SE margin
of the Vienna Basin, the Váh river valley, the Central Eastern
Alps, the Central Western Carpathians, the area of the
thinned crust in the Danube Basin basement, and the Trans-
danubian Central Range (Fig. 12). These domains were de-
termined on the basis of the earthquake occurrence with re-
spect to the crustal thickness, heat flow and the principal
geological units building the domains. In this paper we
present the next step based on definition of zones of
weakness in the upper brittle crust, identified as Paleoalpine
suture zones reactivated during the Late Tertiary, and we de-
fine the seismogenic zones with increased seismic risk in the
area considered (Figs. 7, 13):
A (1, 2) The Vahic suture and above it situated wrench
fault zone accommodating the Western Carpathians extru-
sion northeastwards. The main brittle structures generating
the earthquakes are the Mur-Mürz-Leitha, the Dobrá Voda
and the Povaie fault systems. A maximum epicentral earth-
quake intensity of I
MSK, at the presumed hypo-
center depths as far as 15 km is inferred in this zone.
B (1, 3) The Èertovica suture and above it situated exten-
sional faults which were reactivated during the Miocene
back-arc extension and the following Pliocene isostatic uplift
of the central part of the orogen. The main brittle earthquake-
generating structure is the Hron fault system (surroundings of
Banská Bystrica). The zone is characterized by maximum ep-
icentral intensity of potential earthquakes of I
at presupposed hypocenter depths down to 10 km.
C (1, 2, 3) The Meliata suture and along it situated Hur-
banovo-Diósjenõ fault zone reactivated during the Miocene
extension and wrenching along the Igal-Bükk Zone. This
seismogenic zone is characterized by maximum epicentral
intensity of assumed earthquakes of I
MSK, at in-
ferred hypocenter depths exceeding 15 km.
Acknowledgements: The authors wish to express their grati-
tude to the Grant VEGA No. 13052/96 and EQUIS Ltd. for fi-
nancial support. Constructive remarks of reviewers (L. Cson-
tos, K. Campbell and P. Labák) are gratefully acknowledged.
Bielik M. & Stríenec P., 1994: Flexure of the lithosphere beneath
the Pannonian Basin. Contr. Geophys. Inst. Slov. Acad. Sci.,
Csontos L., Nagymarosy A., Horváth F. & Kováè M., 1992: Tertia-
ry evolution of the intra Carpathian area, a model. Tectono-
physics, 208, 221241.
Èerv V., Pek J., Pícha B., Praus O. & Tobyáová M., 1994: Magne-
totelluric models of inhomogeneity zones. In: Bucha V. &
Blíkovský M. (Eds.): Crustal structure of the Bohemian
Massif and the West Carpathians. Academia, Prague, Spring-
er-Verlag, Heidelberg, 147157.
Fuchs K., Binjer K.P. & Bock G. et al., 1979: The Romanian earth-
quake of March 4., 1977, II: Afterhocks and migrations of
seismic activity. Tectonophysics, 53, 225247.
Fusán O., Ibrmajer J. & Planèár J., 1979: Neotectonics blocks of
the West Carpathians. In: Babuka V. & Planèár J. (Eds.):
Geodynamics investigation in Czechoslovakia, Final Report.
Veda, Bratislava, 187192.
Fusán O., Ibrmajer J., Kvitkoviè J. & Planèár J., 1981: Block dynamic
of the West Carpathians. In: A. Zátopek (Ed.): Geophys. synthe-
ses in Czechoslovakia, Final Report. Veda, Bratislava, 153157.
Fusán O., Biely A., Ibrmajer J., Planèár J. & Rozloník L., 1987:
Basement of the Tertiary of the Inner West Carpathians.
GÚD, Bratislava, 1123 (in Slovak).
Horváth F., 1993: Toward a kinematic model for the formation of
the Pannonian Basin. Tectonophysics, 226, 333357.
Hruecký I., efara J., Masaryk P. & Lintnerová O., 1996: The struc-
tural and facies development and exploration potential of the
Slovak part of the Danube Basin. In: Wessely G. & Liebl W.
(Eds.): Oil and Gas in Alpidic Thrust belts and Basins of Central
and Eastern Europe. EAGE Special Publication. No 5, 417430.
Gutdeutsch R. & Aric K., 1987: Tectonic block models based on
the seismicity in the East Alpine-Carpathian and Pannonian
area. In: Flügel H.W. & Faupl P. (Eds.): Geodynamics of the
Eastern Alps. Deuticke, Wien, 309324.
Jankù J., Pospíil L. & Vass D., 1984: Contribution of remote sens-
ing to the knowledge of West Carpathians structure. Miner.
slovaca, 16, 2, 121137.
Kováè M., Nagymarosy A., Soták J. & utovská K., 1993: Late
Tertiary paleogeographic evolution of the Western Car-
pathians. Tectonophysics, 226, 401415.
Kováè P. & Hók J., 1993: The Central Slovak Fault System field
evidence of a strike-slip. Geol. Carpathica, 44, 155160.
Labák P., 1996: Reinterpretation of the 5.6.1443 earthquake in
Central Slovakia. In: Kaláb Z. (Ed.): Analysis of seismologi-
cal and engeneering geophysical data. Ústav geoniky AV ÈR,
Ostrava-Poruba, 8393 (in Slovak).
Labák P. & Brouèek I., 1996: Catalogue of macroseismically ob-
served earthquakes on the territory of Slovakia since 1034
(1996 version). Geophys. Inst. Slov. Acad. Sci., Bratislava.
Labák P., Brouèek I., Gutdeutsch R. & Hammerl Ch., 1996: The
June 5, 1443 Central Slovakia earthquake. In: ESC XXV Gen-
eral Assembly, Abstracts, Reykjavík, 141.
Lankreijer A.C., 1998: Rheology and basement control on exten-
sional basin evolution in central eastern Europe: Variscan and
Alpine-Carpathian-Pannonian tectonics. PhD thesis, Nether-
lands Res. School Sediment. Geol., Amsterdam, 1158.
Lankreijer A.C., Bielik M., Cloething S. & Majcin D., 1998: Rhe-
ology predictions across the Western Carpathians, Bohemian
Massif and the Pannonian Basin: Implications for tectonics
scenario. Tectonics, in press.
Nemesi L., efara J., Varga G. & Kovácsvölgyi S., 1997: Results
of deep geophysical survey within the framework of the
DANREG project. Geophys. Transact., 41, 143159.
Pìèová J., Petr V. & Praus O., 1976: Depth distribution of the elec-
tric conductivity in Czechoslovakia from electromagnetic
studies. In: Ádam A. (Ed.): Geoelectric and geothermal Stud-
ies. KAPG Geophys. Monogr., Budapest, 517537.
Plaienka D., Puti M., Kováè M., efara J. & Hruecký I., 1997:
Zones of Alpidic subduction and crustal underthrusting in the
Western Carpathians. In: Grecula P., Hovorka D. & Puti M.,
(Eds.): Geological evolution of the Western Carpathians.
Miner. Slovaca, Monography, 3542.
Pospíil L., Schenk V. & Schenková Z., 1985: Relation between seis-
moactive zones and remote sensing data in the West Carpathians.
Proc. 3rd Symp. Anal Seis. Risk. Liblice, Prague, 256263.
Praus O., 1967: Electric conductivity of the Earth in the Czechoslo-
vakia studied by magnetotelluric and geomagnetic methods. In:
Upper mantle project programme in Czechoslovakia 1962
1970. Geophysics, Final report. Academia, Praha, 162186.
Procházková D., Schenk V. & Schenková Z., 1994: Earthquakes in
Central Europe. In: Blíkovský M. & Bucha V. (Eds.): Crustal
Structure of the Bohemian Massif and the West Carpathians,
Academia, Prague, Springer-Verlag, Heidelberg, 6371.
260 EFARA, KOVÁÈ, PLAIENKA and UJAN
Schenk V., Schenková Z., Pospíil L. & Zeman A., 1986: Seismo-
tectonic model of the upper mantle part of the Earth´s crust of
Czechoslovakia. Stud. Geoph. Geod. Prague, 30, 321330.
Schenk V., Procházková D. & Schenková Z., 1994: Seismotectonic
studies in the Bohemian Massif and the West Carpathians. In:
Bucha V. & Blíkovský M. (Eds.): Crustal structure of the
Bohemian Massif and the West Carpathians. Academia, Pra-
gue, Springer-Verlag, Heidelberg, 7684.
efara J., Bielik M., Bodnár J., Èíek P., Filo M., Gnojek I., Grecula
P., Halmeová S., Husák ¼., Janotík M., Král M., Kube P.,
Kurkin M., Leko B., Mikuka J., Muka P., Obernauer D.,
Pospíil L., útora A. & Velich R., 1987: Structural-tectonic
map of the Inner Western Carpathians for the purpose of prog-
nosis of ore-deposits geophysical interpretations. Text to the
collection of maps, 1267 (in Slovak).
efara J., Bielik M., Koneèný P., Bezák V. & Hurai V., 1996: The
latest stage of development of the lithosphere and its interac-
tion with the astenosphere (Western Carpathians). Geol. Car-
pathica, 47, 339347.
imùnek et al., 1991: Results of the Czechoslovak-Soviet exper-
tise determination of sesmic risk. Energoprojekt Praha,
1988, MS, Archive JEBO (in Czech).
teinberg V. et al., 1988: Conclusions about seismic safety of the
nuclear power plant Bohunice. MoskvaPraha, 1988, MS, Ar-
chive JEBO (in Russian).
Tari G., 1996: Extreme crustal extension in the Rába River exten-
sional corridor (Austria/Hungary). Mitt. Ges. Geol. Berg-
baustud. Österr., 41, 1-17.
Tomek È., 1993: Deep crustal structure beneath the central and in-
ner West Carpathians. Tectonophysics, 226, 417431.
Tomek È. & Hall J., 1993: Subducted continental margin imaged
in the Carpathians of Czechoslovakia. Geology, 21, 535538.
Tomek È. & Thon A., 1988: Interpretation of seismic reflection
profiles from the Vienna Basin, the Danube Basin and the
Transcarpathian Depression in Czechoslovakia. Amer. Assoc.
Petrol. Geol. Mem., 45, 171182.
Tomek È., Ibrmajer I., Koráb T., Biely A., Dvoøáková L., Lexa J.
& Zboøil A., 1989: Crustal structures of the Western Car-
pathians on deep reflection seismic profile 2T. Miner. slova-
ca, 21, 326 (in Slovak).
Varga G. & Lada F., 1988: Magnetotelluric measurement on the pro-
file 2T. Unpublished report, ELGI Budapest, Geofyzika Brno.
Vozár J., Tomek È., Vozárová A. & Dvoøáková V., 1995: Deep
seismic profile G: geological interpretation (Inner Western
Carpathians, Slovakia). 15 Congr. Carpath.-Balkan Geol. As-
soc., Spec. publ. 4/1, Geol. Soc. Greece, Athens, 37.