Use of geomorphological indicators for the detection of active faults in southern part of Ljubljana moor, Slovenia

Abstract

In order to detect recently tectonically active faults, Stream Length-gradient (SL) index and a newly developed method of river gradient analysis were made for three rivers. Two methods were used on the southern part of Ljubljana moor, where rivers cross dextral (right-lateral) faults with Dinaric orientation (NW-SE). Watercourse profiles were analysed first, using a »classic«, well established method of SL index. However, this method didn't yield useful results since almost no variability in SL indexes were observed. Additionally, a second newly developed method pointed on the anomalies, which might correspond to the areas of active surface uplift and subsidence as a consequence of active tectonic movements. We compared determined anomalies with the fault lines plotted on the Basic geological map 1 : 100.000 and with the data of radar measurements of vertical movements by PSInSAR method. In this way five potentially active faults, areas of contraction and areas of extension were determined. The results of this research can be used as complementary information for the construction of tectonic model of Ljubljana field and Ljubljana moor.