Appraisal of active tectonics using DEM-based hypsometric integral and trend surface analysis in Emilia-Romagna Apennines, northern Italy

The hypsometric integral (HI) has generally been used to explain the stages of landscape evolution and erosional processes. It is an important tool to investigate tectonics and lithologic and climatic effects on topographic change. We analyzed the significance of the HI to investigate active tectonics in the Emilia-Romagna Apennines of northern Italy. We used a digital elevation model of 5-m spatial resolution to calculate grid-based HI values. The HI distribution does not show clear spatial patterns of high and low HI values. However, when statistical methods of local indices of spatial autocorrelation were applied, it was possible to identify clear clusters of high and low HI values. Trend surface analysis (TSA) was carried out to distinguish areas with anomalously high and low elevations, and to observe their spatial correlation with the HI and regional geological structures. The results indicate that the high HI values and TSA anomalies are positively correlated with the areas of high tectonic activity and along the regional tectonic structures.