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Vorträge und Posterpräsentationen (mit Tagungsband-Eintrag):

G. Timár, B. Székely, A. Zámolyi, G. Houseman, G. Stuart, B. Grasemann, E. Dombrádi, A. Galsa, S. Spahic, E. Draganits:
"Neotectonic implications by geophysical surveys of topographic features identified by Airborne Laser Scanning in the Neusiedlersee/Ferto area (Austria/Hungary)";
Poster: EGU 2009, Vienna; 19.04.2009 - 24.04.2009; in: "Geophysical Research Abstracts", 11 (2009), Paper-Nr. EGU2009-9240-1, 1 S.



Kurzfassung englisch:
The area around the Lake Neudsiedlersee (Lake Fert˝o in Hungarian) was analysed to understand its neotectonic
activity and gather possible explanations of the features of the topography and microtopography.
The area consists of two, considerably different parts in terms of topography and geomorphology. The
western and north-western shores of the lake are connected to the Leitha Mts., a low ridge (its relative height
is about 300 meters) that connects the Alpine orogen in the SW with the Carpathians to NE bounded by active
strike-slip faulting. In this part of the area, several outcrops were investigated, of which the one at St. Margarethen
was systematically measured by multielectric sounding and GPR, and an other one at St. Georgen, north of
Eisenstadt, was used for auxiliary data gathering. The eastern and southern shores, belonging to the Pannonian
Basin, are mostly flatlands, parts of the Little Hungarian Plain with extremely low relief and no real natural
drainage. The small variations of the surface altitude (less than ten meters), referred to as microtopography here,
are due to elongated ridges and extremely shallow perennial or temporal playa lakes. In order to understand better
the subsurface structure, a multimethod approach has been applied.
Geophysical survey methods (vertical electric sounding, land seismics, gravity measurements) were carried
out to describe the layer structure of this area, especially a zone, north of Illmitz, connected to interesting elements
of microtopography. The identification of microtopographic features were carried out using high resolution digital
elevation datasets, derived from Aerial Laser Scannings (ALS). Seismic measurements were carried out also in
the lake itself to understand the structural geological settings of the lake bottom to the depth of ca. 50 meters. All
of these measurements were made in the framework of a common student fieldwork of the Eötvös University, the
University of Leeds and the University of Vienna.
Fault lines that can be interpreted active in neotectonic point of view were found below the lake by water
seismic. These faults displaced young sediments as well. Similar patterns were found at the outcrop of St. Margarethen
near to the western shore of the lake and were followed underground by the geophysics. However, in the
eastern shore the geophysics showed no sign of active tectonics in the upper fifty meters of the sediment. Changes
in physical characteristics (resistivity, wave propagation velocity) were mapped in 3D and were connected to the
ALS microtopographic features. The material of the small elevated zones occurred to be gravel and coarse sand
and the basement of this layer was a low-resistivity clay. Previously these structures were interpreted as large-scale
deformations bands; this solution is still feasible in the light of the results. A further possible interpretation of this
structure is that the topographic undulations are connected to the former alluvial fan of the Paleo-Danube River,
sedimented from north.


Elektronische Version der Publikation:
http://publik.tuwien.ac.at/files/PubDat_175578.pdf


Erstellt aus der Publikationsdatenbank der Technischen Universitšt Wien.