High resolution techniques for morphological studies in volcanic areas

Over the last decades the terrain morphologic studies were greately improved thanks to the introduction of increasingly accurate terrain modeling techniques. Recently, in volcanic areas the simultaneous use of photogrammetric and geodetic (GPS) sur- veys was experimented with the aim to generate and validate accurate digital terrain models (DTM), that is numerical rapresentations of the topographical surface. Their availability allows to execute quantitative analysis of the terrain shapes and their vari- ations, to extract morphological parameters (volume, slope and drainage patterns) and to evaluate crustal deformations. Therefore, it is possible to identify the morphological processes and the related surface forms that characterize the volcanic structures. The study case proposed in this paper involves the Vulcano and Stromboli islands (Aeolian Arc, Italy). Since 1992, the Aeolian Arc has been subjected to photogrammetric and GPS survey, whose data have allowed to obtain three-dimensional models. The com- bination of digital terrain models and aerial photos provides digital map products that support the identification of particular morphologies and tectonic structures. Futher- more, by processing the DTM in a GIS framework, morphometric parameters maps can be obtained. The importance of morphometric parameters, such as slope, aspect, plan and profile convexity, is due to their control influence on the slope dynamics, on relief features and, specially for convexity parameters, on the slope drainage. By combining the morphometric parameters maps and ortophoto with a geologic map, is possible to derive a geomorphological maps. The described products turn out partic- ularly interesting in active zones, where the morphology is in continuous evolution because of the landslides or lava flows, because allows to perform periodical updating of high resolution mapping products and consequently to have a constant control on the morphologic evolution of the area. Moreover, the comparison of two DTMs of the same area relevant to successive epochs, allows to realize a morphologic processes quantitative analysis, such as to estimate the landslide body volume or to misure the crustal deformation. This approach was applied to Vulcano IslandSs NE flanks and to Etna volcano.