Geomorphological detection of surface effects induced by active blind thrusts in the southern Abruzzi peri-Adriatic belt (Central Italy)

Abstract

In clayey-sandy regions, deformed geomorphological features, such as river channels and terraces, may represent valuable indicators of ongoing tectonic activity. In this perspective, geomorphometric indexes have been developed, among which the SL and ksn indexes seem to be the most efficient to detect tectonically-induced stream anomalies. In the present study, we used these indexes to investigate the possible activity of the easternmost fold-and-thrust system of the Apennine orogen, mostly buried under a thick sequence of post- orogenic, clayey-sandy marine deposits, in a sector of Abruzzi located between the Maiella piedmont and the Adriatic coast. Whereas most authors consider these structures tectonically inactive, several others argue that they still undergo compression. In particular, we used the SL and ksn indexes to identify surface deformations possibly induced by the ongoing activity of the buried structures. Moreover, based on geological-geomorphological field survey, supported by remote sensing and spatial data handling (TINITALY Digital Elevation Model, and the MATLAB® and QGis software products), we surveyed the tread profiles of river terraces in selected valley sectors. The investigation results agree in confirming the ongoing activity of the buried structures as well as the noteworthy effectiveness of the methods applied.