Tectonic activity assessment using morphometric indices - Tokaj Mountain (Hungary)

The Tokaj Mountain in North eastern Hungary is part of the andesitic and dacitic volcanic arc of the inner Carpathians. The mountain is surrounded by first order strike-slip faults from the W and SE side respectively called as the Hernád Fault and Bodorg Fault. These faults are moderately active today, in the interior of the mountain range. However, there are few rock outcrops indicative of structural movement, but the morphology of the watercourses suggests that the area was more active in the recent past.

The present study aims to examine the link between the actual morphology of the mountain and the major tectonic factors affecting the region. In this regard, a morphometric analysis was performed adopting six indices in order to describ the relative active tectonism of the region based on the method of El Hamdouni et al.(2008). 

The method consists of the analyis of drainage basins and includes the evaluation of the morphometric indices namely: the stream-gradient index (SL), the asymmetry factor (AF), the basin shape ratio (Bs), the hypsometric integral (HI), the ratio of valley floor width to valley height (Vf) and the mountain front sinuosity (Smf). The combination of these parameters could be used to generate the relative tectonic activity index (Iat). A pre-processed SRTM DEM 30m resolution has been used for the watershed delineation, calibrated with open source real stream data. 

The study area covers the entire catchment area of the Hernád River the Tokaj and the Cserehát Mountains devided into six drainage basins. The evaluation result shows a moderate relative tectonic activity, except the eastern side of the mountain, where  the activity is low (flat area). However, there was also a slight difference in activity between the western and eastern sides of the lower Hernád River, and also a remarquable morphological  contrast could be noticed on the bordering areas of Hernád drainage basin. The results are in line with the relatively quiet structural activity currently observed, but further detailed data (well logs, interferometry analysis) and high resolution DEM are needed to reveal the structural characteristics of the Tokaj Mountains.

From the part of G.A. financial support was provided from the NRDI Fund of Hungary, Thematic Excellence Programme no. TKP2020-NKA-06 (National Challenges Subprogramme) funding scheme.

Reference:

El Hamdouni et al (2008). Assessment of relative active tectonics, southwest border of the Sierra Nevada (southern Spain), Geomorphology, 96(1-2), 150-173.