Large scale aerial photogrammetry for mapping and detecting morphological changes in volcanic areas (Vulcano and Stromboli Island, Italy)

Large scale maps and 3D data derived by digital photogrammetric processing have recently demonstrated remarkable potentialities for studies of tectonically and volcanically active regions. By using photogrammetric derived data it is possible to precisely define the geometry and the changes of morphological features of ground surfaces, to identify the gravitative instability phenomena induced by volcanic activity and to detect and map areas involved in crustal deformations phenomena. Digital Elevation Model, DEM, derived by combining data from large scale aerial photogrammetric surveys with Global Positioning System (GPS) provide submeter elevation accuracy. Multitemporal DEM acquired periodically allow us to detect areas interested by crustal deformations, to evaluate mass balance in case of large instability phenomena and lava flows occurrence. The work describes the results obtained from the analysis of photogrammetric data collected over the Vulcano Island from 1971 to 2001 and on the Stromboli Island in 2001 and immediately after the occurence of the major landslide of December 2003. The data, processed by means of the automatic correlation module included in the Digital Photogrammetry Workstation DPW770, provided DEM with accuracy ranging between few centimeters to few decimeter depending on the geometric image resolution and terrain characteristics.