Identification of tectoni cally active areas using DEM: A quantitative morphometric anal y sis of mt. medvednica, NW Croatia

Abstract

Mt. Medvednica is an inselberg in NW Croatia, which lies at the intersection between the Southeastern Alps, Northwestern Dinarides and Tisza Mega-Unit of the Pannonian Basin. Due to the Pliocene-Quaternary N-S directed shortenl ng, Mt. Medvednica experienced 1500-2000 m of differential uplift and now exposes pre-Neogene and Neogene tectonic and strati-graphic units that are surrounded by Pliocene-Quaternary sed iments. This paper evaluates a set of quantitative morphometry methods used to identify tectonically active areas within this region characterized by low-rate aclive folding and faulting during the Pliocene-Quaternary. Our analysis employed exlraclion of hypsometric curves, calculation of a hypsometric integral, asymmetry factor, and statistical parameters of longitudinal stream profiles along 36 drainage basins delineated from a 25 m resolution DEM of Mt. Medvednica area. Despite lithological heterogenelty of the study area, the morphometric parameters we obtain are good indicators for discriminating tectonically active from inactive areas. We interpret that the most tectonically active areas are located at the SW corner and in the central part of Mt. Medvednica, where they are likely related to the North Medvednica Boundary Fault, and to the Kasina Fault, respectively. The latter divides the range into distinct NE and SW morpho logical and structural areas.