Identification of tectonically active areas using DEM : a quantitative morphometric analysis of Mt. Medvednica, NW Croatia

Mt. Medvednica is an inselberg in NW Croatia which tectonically lies at the intersection between Southeastern Alps, Northwestern Dinarides and Tisza Mega-Unit of the Pannonian basin. Due to the Pliocene-Quaternary N-S directed transpression it experienced a differential uplift between 1500-2000 m and exposes pre-Neogene and Neogene tectonic and stratigraphic units surrounded by Pliocene-Quaternary sediments. This paper evaluates a set of methods in quantitative morphometry, used here for identification of tectonically active areas within a region characterized by low-rate active folding and faulting during the Pliocene-Quaternary times. Analysis employed extraction of hypsometric curves, calculation of hypsometric integral, asymmetry factor, and statistical parameters of normalized longitudinal main stream profiles of 36 drainage basins delineated from a 25-m resolution DEM of Mt. Medvednica area. Despite lithological heterogeneity, obtained morphometric parameters are considered as fairly good indicators for discriminating tectonically active from inactive areas. Based on calculated parameters, in combination with geological data, the most tectonically active areas during the Quaternary are found at the SW corner of the Mt. Medvednica related to an active segment of the North Medvednica Boundary Fault, and in the central part of the mountain related to the Kašina fault zone subdividing mountain into the NE and SW units