River terraces in the Fiume Tronto drainage basin (Marche Region): a contribution to morphotectonic investigations

Abstract

The aim of this work is to provide a methodological input based on geostatistical topographic analyses for the detection of morphological anomalies induced by neotectonic activity on fluvial terrace surfaces. The study area corresponds to the distal portion of the Fiume Tronto drainage basin (Southern Marche region of Central Italy); the basin developed on Plio-Pleistocene marine terrigenous deposits and its arrangement was strongly influenced by Quaternary uplift and regional WSW-ENE and E-W trending fault zones. Detailed surveys allowed to verify the location of surfaces, at several levels; they are the remnants of Quaternary fluvial terraces, formed in response to both climatic oscillations and regional uplift. Several points at the top of the surfaces were sampled by GPS and then geostatistically processed (Kriging method) to provide an unbiased interpretation of the chronological sequence of terraces. The geometrical setting of the terraces seems strongly influenced by the regional uplift and by the activity of the Tronto major fault. Results of geostatistical analysis, compared to the DTM indicated that minor Quaternary faults dislocated the terraces. This is in agreement with the outcomes of previous works, thus confirming the usefulness of this methodological approach in the study of fluvial terraces as neotectonic indicators.