Remote sensing of volcanic terrains by terrestrial laser scanner and RGB data: a case study from the

Abstract

This work focuses on the use of terrestrial laser scanner (TLS) in the characterization of volcanic environments. A TLS survey of the Vesuvius crater (Somma-Vesuvius volcano, Italy) allows the construction of an accurate, georeferenced digital model of different sectors of the crater. In each sector, the intensity is computed for each point as the ratio between the emitted amplitude and the received one, normalized to the maximum signal, providing the radiometric information. Moreover, the RGB colours of the observed surfaces are collected by means of a calibrated camera mounted on the TLS instrument. In this way, multi-band information is given, since a long range TLS operates in the near infrared band. The radiometric and RGB data are compared in order to verify if they are independent enough to be complementary for model analysis and inspection. The results show that, even if the RGB data are agreeable, a complete study of volcanic environments can be based on radiometric data only. The collected data are able to discriminate different volcanic deposits and to reconstruct their stratigraphy. In addition, our results shed light on the spatial extension of landslides and on the dimensions of rock fall/flow deposits affecting the inner walls of the crater. The remotely acquired TLS information from the Vesuvius crater is compared with that from a sedimentary terrain (coal-shale quarry) to detect possible similarities/differences between these two geological environments.