Michele Santangelo, Francesco Mirabella , Francesco Bucci, Ivan Marchesini, Mauro Cardinali, Fausto Guzzetti, 2014, Application of remote sensing data and GIS techniques to the study of the morpho-structural features of extensional basins_ an example from the Montefalco area (northern Apennines, Italy)., GIT, 2014, Montefalco, 16-18 Giugno, 2014,
URL: http://www.cnr.it/prodotto/i/303487

In areas undergoing extensional faulting, the investigation of the tectono-sedimentary evolution of fault-controlled basins through the analysis of morpho-structural features can provide valuable information on the space-time evolution of the active deformation. To this extent, remote sensing data provide a precious source of information that can successfully integrate traditionally collected field data. In this work, we focus on the Montefalco ridge, which topographically separates the Gualdo Cattaneo and Foligno valleys and which represents an inversion of relief being composed of fluvial sands of conglomerates now uplifted more than 200 m above the present day alluvial plain. We carried out a systematic aerial photo-interpretation of two sets of aerial photographs, one flown in 1977 (colour) and one flown in 1997 (black and white). We collected a set of photo-geological data, including Quaternary faults, bedding traces (i.e. the intersection lines between the geological bedding and the topographical surface), and lithological boundaries. Data were transferred to obtain a 1_10,000 scale map. All the aerial photographs were orthorectified to reduce mapping errors when transferring information from the aerial photographs to the topographic base map. In particular, we exploited the i.ortho.photo tool of GRASS GIS, using as data in input a 1m resolution orthophoto taken in 2006 and available as WMS service on the National Cartographic Portal, and a 10m resolution DEM. We then used the GRASS GIS tool geobed.py (http://geomorphology.irpi.cnr.it/tools/gis-and-interpretation-of-aerial-photographs/geobed.py/view) to obtain the bedding attitude starting from the bedding traces and the 10m resolution DEM. Using the same approach we also obtained the attitude of the fault planes. We carried out field checks to validate the photo-geological information. Our results show that aerial photo-interpretation overcomes the main limitations of the traditional field mapping approach since it allows collecting spatially distributed information on fault planes and bedding attitude. The integration of the traditional field structural geology approach and the photo-geological information provides a more complete dataset, which allows making inferences on the tectono-stratigraphic evolution and deformation pattern of the studied basin. We believe this approach can have several other applications in geosciences, such as slope stability analyses, validation of geological profiles, exploration geology, and morpho-tectonic studies.

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