Neotectonic control on landscape evolution in the Little Hungarian Plain

Autor(en)

Andras Zamolyi

Abstrakt

The deep structure of the Little Hungarian Plain (LHP) and adjacent areas is dominated by tectonic processes related to the lateral extrusion of the Eastern Alps and the acceleration of northward movement of the Carpathians. Subsidence in the Little Hungarian Plain in the Lower Miocene is mainly accommodated along major high-angle normal faults without significant pull-apart component. The reactivation of these Neogene structures contributes to a major part to the pattern of active faulting within the region. Joó (1998) measured recent vertical crustal movements with values up to -2.2 mm/a in the northern and with -0.6 mm/a in the southern part of the LHP interpeting this as an evidence for faulting. Based on structural field data, the recent stress field is found to be influenced by strike-slip faulting linked to normal and thrust faults. Our investigations focus on the control of active faulting on the geomorphology and drainage system in this very low-relief area. The study area is located in the westernmost part of the Little Hungarian Plain and belongs to the catchment of the Danube River. The channel pattern of the Leitha, Répce, Rábca, Ikva and Wulka rivers were analysed in order to detect a possible relation between channel geometry and on-going tectonic activity. Exactly georeferenced historical maps of the Second Military Survey of the Habsburg Empire that record the channel patterns and geomorphologic situation around 1840 were used for channel geometry extraction. This provided the basis for the calculation of river sinuosity values using several window sizes. Calculated river sinuosity values show surprisingly strong local variations, considering the low relief and lithologic homogeneity of the area. The spatial distribution of the pronounced sinuosity variations coincides with the location of Late Miocene faults, well-known from seismic sections. Ongoing active tectonic activity at these faults is further indicated by the local earthquake record and geomorphic features. The surface expression of these Late Miocene faults cannot be derived from industrial seismic surveys, since approximately the upper 300 m are generally muted. However, high-resolution digital elevation models (e.g. ALS DTM data) allow detection of micro-topographic changes at the surface that are probably related to neotectonic features. Combined analysis of river sinuosity values and data derived from high-resolution digital elevation models improve the mapping of the faults at the surface.

 

Joó I., 1998. Magyarország függőleges irányú mozgásai (Vertical crustal movements in Hungary). Geodézia és Kartográfia, 50, 3-10

Organisation(en)

Institut für Geologie

Seiten

119-120

Anzahl der Seiten

222

Publikationsdatum

2008

ÖFOS 2012

105404 Geomorphologie, 105101 Allgemeine Geologie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/73b289f4-788a-4139-bc36-a94fc2075b21