GNGTS 2021 - Atti del 39° Convegno Nazionale

423 GNGTS 2021 S essione 3.2 is located in an urban environment and is composed by both municipal and construction waste, with its geometry and composition documented elsewhere (e.g., Flores Orozco et al., 2020 and references therein). This study aims at improving the delineation of the landfill geometry and the contact between municipal and construction waste in its south-eastern end. The obtained quasi- 2D shear-wave velocity section shows a shallow low velocity zone in the north-western part of the section, extending down to 4 meters, which could correspond to the municipal waste deposit (Fig. 1a). Around x = 180 m, the seismic velocities smoothly increase, indicating a transition from urban to excavation waste. Electrical resistivity tomography (ERT) and electromagnetic data measured along the same line show a sudden change in conductivity values at the same location (Fig. 1b), validating the results of the surface-wave inversion. This interpretation is in agreement with the direct measures of Brandstätter et al. (2013) and Valtl (2005) and with more recent geophysical studies from Flores-Orozco et al. (2020). This study demonstrates that the implemented linear inversion scheme can be effectively applied to small-scale environmental problems, where generally seismic methods are scarcely adopted. References Boschi L. and Dziewonski A. M.; 1999: High- and low-resolution images of the Earth’s mantle: Implications of different approaches to tomographic modelling . J. Geophys. Res., 104 , no. B11, 25,567-25,594. Brandstätter C., Laner D. and Fellner J.; 2013: Site specific in-situ aeration completion criteria: case study “Heferlbach” . In: Sinks a vital element of modern waste management - 2nd international conference on final sinks, Espoo, Finland. Flores-Orozco A., Gallistl J., Steiner M., Brandstätter C. and Fellner J.; 2020: Mapping biogeochemically active zones in landfills with induced polarization imaging: the Heferlbach landfill . Waste Manage (Oxford), 107 , 121–132. Gouédard P., YaoH., Ernst F. andVan der Hilst R. D.; 2012: Surfacewave eikonal tomography in heterogeneous media using exploration data . Geophys. J. Int., 191 , 781–788. Mordret A., Roux P., Bouè P. and Ben-Zion Y.; 2019: Shallow three-dimensional structure of the San Jacinto fault zone revealed from ambient noise imaging with a dense seismic array . Geophys. J. Int., 216 , no. 2, 896–905. Pilz M., Parolai S., Picozzi M. and Bindi D.; 2012: Three-dimensional shear wave velocity imaging by ambient seismic noise tomography . Geophys. J. Int., 189 , no. 1, 501–512. Shapiro N. M., Campillo M., Stehly L. and Ritzwoller M. H.; 2005: High-resolution surface-wave tomography from ambient seismic noise . Science, 307 , 1615-1618. Trampert J. and Woodhouse J. H.; 1996: High resolution global phase velocity distributions . Geophys. Res. Lett., 23 , no. 1, 21-24. Valtl M.; 2005: Altablagerung “Heferlbach”: Gefährdungsabschätzung und prioritätenklassifizierung . Tecnical report, Umweltbundesamt. Email address of the first author: ilaria.barone@unipd.it