Evaluation of Morphometric Indices SL, LP, AD for the Spatial Analysis of Neotectonics and Recent Crustal Deformations Case study: Atlas Central, Tunisia

Abstract

Our study endeavors to evaluate some morphometric indices that are selected according to several statistical studies and applied in Quaternary lithological formations. Our study area is the Tunisian Central Atlas, which is known by a Quaternary deposit that can reach 400 m. Because of certain constraints related to remote sensing limitations for the tectonic lineaments mapping in the quaternary and the lack of terrain index in most cases in these deposits, we are interested in spatially analyzing the response of tectonics to these morphometric indices among others, Stream Length (SL), Longitudinal Profile (LP) and Drainage Anomaly (DA). Our proposed methodology consists of evaluating, on the one hand and independently, the tectonic response to morphometric indices. On the other hand, we aim at spatially and arithmetically combine the density of SL, LP, DA by an equivalent weighting for these three indices in order to locate all the zones, detected by the one of indices or the other, and which are sensitive to recent deformation or neotectonics. The calculation of these three morphometric indices (SL, LP, DA) is their representation in terms of density, which allows us to evaluate each of them. The result obtained is consistent with some field surveys in the Kasserine plain Quaternary deposit. However, the cartographic spatial analysis through the maps of the density distribution of each index, lead us to combine the three indices in order to improve the spatial analysis by an equivalent arithmetic weighting to finally generate the high-density zones to prove the existence of recent deformation or neotectonics (the Kasserine plain) and the low density medium zones according to the synthesis map of the combination of the densities of the three indices.