First Break - Volume 43, Issue 8, 2025

Electrical Resistivity Tomography (ERT) and induced polarisation (IP) methods are widely employed in the characterisation of urban landfills due to their sensitivity to subsurface moisture and electrochemical properties of waste. Traditional local inversion techniques, typically based on smoothness-constrained Occam-type methods, can fail to resolve the high spatial variability of leachate accumulation areas. Additionally, these techniques do not provide an assessment of the uncertainty associated with the detection of accumulation areas, which is pivotal for informing quantitatively the landfill management. In this study, we apply a global inversion approach based on the Very Fast Simulated Annealing (VFSA) algorithm to ERT and IP datasets acquired on a municipal solid waste (MSW) landfill located in Central Italy. This site, characterised by a steep slope and high risk of lea-chate-induced instability, is currently monitored with time along multiple profiles. The global inversion process was implemented on a selected line where also piezometric level logged in wells are available. Posterior model ensembles were also analysed to derive uncertainty estimates, and petrophysical transformations were applied to extract water content and Cation Exchange Capacity (CEC) from the geoelectrical parameters. The results demonstrate the effectiveness of the VFSA method in detecting highly variable leachate zones, as confirmed by the good agreement with leachate levels logged in wells. The uncertainty assessment highlighting areas of higher and lower reliability of the geophysical model can further support the landfill monitoring, with implications for risk assessment and long-term management.

Uruguay’s commitment to incorporating non-traditional indigenous renewable energy sources into the national energy matrix represented a fundamental step towards energy independence. The country successfully transitioned from having no wind energy in its electrical distribution system to currently ranking among the world leaders in terms of wind power participation in its energy matrix. This study presents a survey campaign conducted at a productive wind farm site and on a wind tower structure using the horizontal-to-vertical spectral ratio (HVSR) method, multichannel analysis of surface waves (MASW), and seismic refraction tomography. Seismic velocities and ground accelerations were measured over a long period of time, obtaining environmental vibration records collected at various points on the structure and in the surrounding subsoil. The HVSR of microtremors recordings was used to extract relevant information from the data such as the natural vibration frequencies of the structure and underlying ground. The shear and compressional seismic wave velocities were calculated. These results may have applications in the correct site selection for future wind farms, in the design of wind turbine structures, as well as in monitoring and determining the structural health of existing wind towers.