Evaluation of tectonic activity using morphometric indices: case study of the Tatra Mts. (Western Carpathians, Poland)

Abstract

The Tatra Mountains (Tatra Mts.) are the highest and most glacially reshaped mountain massif in the Carpathians. Previous studies suggested the tectonic uplift of this massif along the large sub-Tatric fault during Quaternary. The main goal of this paper is to characterise the tectonic activity in the Tatra Mts. using 6 geomorphic indices for 78 drainage basins: the stream-gradient index (SL), asymmetry factor (Af), basin shape ratio (Bs), hypsometric integral (Hi), valley floor width–valley height ratio (Vf), as well as mountain-front sinuosity (Smf). These parameters were combined in order to obtain the relative tectonic activity index (Iat) using GIS. The average of the six computed geomorphic indices was used to evaluate the distribution of relative tectonic activity in the study area. According to Iat values, four classes of different tectonic activity can be distinguished in the Tatra Mts.: class 1 of very high tectonic activity (0.7% of Tatra Mts.); class 2 of high activity (24.3%); class 3 of moderate activity (68.4%); and class 4 of low activity (6.6%). Our study confirmed previous suggestions about unequal uplift of different parts of the massif. Iat values show high tectonic activity along the Sub-Tatric fault, as well as in the northern part of the Belianskie Tatra. Distribution of Vf and Hi values correlate with extend of glaciers during Last Glacial Maximum. It seems that values of some geomorphic indices, such as Vf and HI, are strongly associated with glacial reshaping of the Tatra Mts. during the Pleistocene.