The changing face of Mount Etna's summit area documented with Lidar technology

Morphostructural data derived from Lidar ( Light detection and ranging) surveys carried out on Mount Etna in 2005 and 2007 are compared with earlier aerophotogrammetric surveys in 1986 and 1998. These data render an unprecedentedly clear and quantitative image of morphostructural and volumetric changes that have affected the summit area of the volcano in the past two decades and permit the production of a new topographic map. The computed volume gain during the 1986-2007 period amounts to 112 +/- 12 X 10(6) m(3), at a mean annual rate of similar to 5.3 X 10(6) m(3). The comparison of the various surveys furthermore emphasizes the levels of accuracy and resolution of the different techniques applied. The Lidar technology used in 2007 allows production of high-precision maps in near-real-time, facilitating work concerning environmental hazards such as numerical simulations of, e. g., lava flows.