Chiara Colombero

Continuous passive seismic monitoring has provided insights into detecting and tracking the evolution of the rock mass responses under hydro-mechanical processes at multi-daily timescales. The Bossea Cave is a mountain karst aquifer located in the Ligurian Alps (Piedmont, NW Italy). It developed at the contact between a Permian impermeable meta-volcanic basement and an overlying Triassic meta-carbonate sequence. This upper unit controls the drainage of infiltrating water, mainly driven by rainfall and snowmelt processes occurring in the aquifer’s recharge area. The seismic signature of these water inflows was investigated using a three-component seismometer installed in the hypogeal environment. Ambient-noise Power Spectral Density (PSD) was computed on each component to identify high-energy frequency bands and examine their temporal evolution, comparing it with the discharge trends of the main drain (Mora Creek). A strong correlation was detected at approximately 33 Hz on the North, East, and vertical components, with a zero-lag response under ordinary recharge conditions. In contrast, during extreme inflow events (e.g., October 2020), increases in seismic-noise amplitude preceded the discharge peak by approximately 4 hours. These observations complement the results of a temporary external seismometer survey deployed on the slope above the cave in 2022, where precipitation-driven modulation was identified in the 50–90 Hz band and a 30-Hz amplification occurred about 4 hours before the peak discharge. This combined evidence provides a basis for investigating the triggering mechanisms of coupled thermo- and hydro-induced rock-mass deformation and for characterizing the spectral signatures of impulsive microseismic signals potentially associated with incipient fracturing.

Permafrost degradation in alpine regions driven by climate warming is increasing the likelihood of rock slope destabilization. However, the mechanical response of fractured rock-ice systems to repeated freeze-thaw cycles and long-term warming remains poorly monitored and understood. Using a decade of continuous passive seismic data recorded at different stations, this study investigates how seasonal and long-term environmental forcings affect the mechanical properties of a steep bedrock permafrost site at the Matterhorn Hörnligrat ridge (Valais, Switzerland). We applied spectral analysis (single-station and site-reference spectral ratios), auto- and cross-correlation of ambient seismic noise combined with microseismic event detection and analysis to track the long-term temporal variations and evolution in resonance frequencies and seismic wave velocity within the rock mass, and in the spectral characteristics of microfracturing events. We observed strong, reversible seasonal variations of mechanical parameters linked to freeze-thaw cycles, characterized by reduced stiffness in summer and increased stiffness in winter. Long-term observations showed a continuous decrease in resonance frequencies, wave velocities, and peak frequencies of the microseismic events, indicating progressive and irreversible mechanical weakening of the rock-ice system. These results demonstrate that passive seismic monitoring enables the detection of both reversible and irreversible mechanical changes in alpine permafrost slopes, providing early indicators of progressive destabilization under ongoing climate warming.

We present a collaborative research initiative involving Politecnico di Torino (Italy), Ilia State University (Georgia), and Telavi State University (Georgia) aimed at developing and implementing customized Early Warning Systems (EWS) for landslide risk mitigation. The research is carried out at strategic pilot sites in Georgia, a region characterized by high geological complexity and significant susceptibility to slope instability. Two Georgian pilot sites are located in the Kakheti Region, within the Gombori Range of the Alazani River basin (eastern Georgia), and in the Vere River basin, a right-bank tributary of the Kura River, southwest of the capital city, Tbilisi. A first phase focuses on site characterization based on integrated geological, geophysical, geotechnical, and geomatics surveys. This phase aims to define lithological sequences, material properties, and slope geomorphological features to identify the dominant failure mechanisms. The geomatics methodology involves the use of GPS devices, photogrammetric analysis and drone-based LiDAR surveys. The adopted geophysical methods mainly combine electrical resistivity tomography (ERT) and seismic refraction and surface wave analyses. Geological characterization and modeling further include lithological and structural analyses, identification and mapping of existing landslide and debris-flow bodies using photogrammetry and satellite image analyses, estimation of the approximate volume of mobilized sediments in different catchments within the study area, and the collection of geological information required to model the potential distribution of landslide-related debris flows.The second phase addresses the EWS design for the development of a monitoring framework primarily based on geophysical and geomatics methodologies. Attention is also given to the monitoring of the landslide-induced microseismicity associated with fracture processes and slope movements. The EWS is customized with sensor configuration and threshold parameters specifically designed for the types of landslide phenomena identified during the first phase. The overall goal is to develop a methodology for protecting infrastructures and local communities from landslide triggering; by integrating multi-sensor data fusion with site-specific geological and hydogeological models, the project aims to establish a robust framework for real-time monitoring and early warning, providing a scalable approach to landslide risk management.

Velocity models of the shallow subsurface (a few hundred meters) are important in near-surface characterization, improving seismic mapping resolution at depth, and constraining deeper geological models. It is therefore interesting to retrieve them from deep seismic exploration data. We compute the near-surface shear wave velocity model in the vicinity of South Deep Gold Mine, using surface waves present in the small-offset 2D and 3D seismic reflection data acquired between 2022 and 2023 at the mine for research, mine planning, and development purposes. The obtained near-surface model is then used to (1) characterize the near-surface, and (2) better constrain the interpretation of possible water preferential flow-pathways (faults, fracture zones, and dykes) mapped at mining levels, that enable the migration of water from overlying aquifer systems (< 0.5 km depth) to the mining levels (∼ 3 km depth). The analysis is carried-out on reflection seismic data acquired for deep mineral exploration, where the acquisition parameters were not optimized for surface wave techniques and the reciprocity principle is used to improve the data density, coverage, and near-surface mapping resolution. The lithostructural information retrieved from the produced pseudo-2D and 3D shear wave velocity models is consistent with information obtained from available surface borehole data and published records in the study area. To investigate the structural linkage between the deep mining levels and shallow groundwater aquifers, we integrated the near-surface shear wave velocity model produced from the small-offset 2D and 3D reflection seismic data with the large-offset 2003 3D reflection seismic data, and geological structures derived from underground mapping, and exploration drilling. The shear wave velocity models help define the faults, fractures, and dykes that compartmentalize the near-surface groundwater aquifer systems. The large-offset legacy 2003 3D seismic data, underground mapping, and exploration drilling provide a better definition of the orebody and its offsets (e.g., faults) at the mining level. The integrated data show that several geological structures (e.g., faults and dykes), defined by legacy seismic data, underground drilling, and mapping, cross-cut the mining levels at ∼ 3 km depth and intersect the near-surface aquifers, thus making these structures possible preferential flow-pathways for water migration to the deep mining levels. The results of the interpretation illustrate the advantages of integrating shallow and deep subsurface information to constrain the timing of geological events and mitigate the risks associated with water ingress to the mining levels. The final model produced can be used for future mine development, improving safety and production, and for the extension of the Life of Mine (LoM).

Velocity models of the shallow (a few hundreds of meters) geology are hardly retrieved from deep seismic reflection exploration data, despite their importance in near-surface characterization, improving seismic mapping resolution at depth, and constraining deeper geological models. In this work, we compute the near-surface shear wave velocity model in the vicinity of South Deep Gold Mine, using surface waves present in the 2D and 3D deep seismic reflection data acquired at the mine. The obtained near-surface model is then used to (1) characterize the near-surface and (2) better constrain possible water conduits (faults, fracture zones and dykes) mapped at mining levels, that enable the migration of water from overlying formations to the mining levels, and (3) constrain the timing of faults and dykes activity in the vicinity of the mine. The analysis is carried-out on reflection seismic data acquired for deep mineral exploration, where the acquisition parameters were not optimized for surface wave techniques, thus the reciprocity principle is used to improve the data density, coverage, and near-surface mapping resolution. The lithostructural information retrieved from the produced pseudo-2D and -3D shear wave velocity models are consistent with information obtained from available borehole data and published records in the study area. Integrating the produced near-surface shear wave velocity model with a legacy 2003 P-wave seismic reflection cube, mine mapping and drilling information enabled the investigation of the structural linkage between the near-surface groundwater aquifers and deep mining levels (~ 3 km depth). The faults and dykes mapped at the mining level intersect and cross the near-surface aquifers, thus making these structures possible conduits for water migration to the deep mining levels. The findings of this research illustrate the advantages of integrating shallow and deep subsurface information to constrain the timing of geological structures and mitigate the risks associated with water ingress to the mining levels. The final model produced can be used for future mine development, improving safety and production, and for extending the Life of Mine (LoM).

Velocity models of the shallow (a few hundreds of meters) geology are hardly retrieved from deep seismic reflection exploration data, despite their importance in near-surface characterization, improving seismic mapping resolution at depth, and constraining deeper geological models. In this work, we compute the near-surface shear wave velocity model in the vicinity of South Deep Gold Mine, using surface waves present in the 2D and 3D deep seismic reflection data acquired at the mine. The obtained near-surface model is then used to (1) characterize the near-surface and (2) better constrain possible water conduits (faults, fracture zones and dykes) mapped at mining levels, that enable the migration of water from overlying formations to the mining levels, and (3) constrain the timing of faults and dykes activity in the vicinity of the mine. The analysis is carried-out on reflection seismic data acquired for deep mineral exploration, where the acquisition parameters were not optimized for surface wave techniques, thus the reciprocity principle is used to improve the data density, coverage, and near-surface mapping resolution. The lithostructural information retrieved from the produced pseudo-2D and -3D shear wave velocity models are consistent with information obtained from available borehole data and published records in the study area. Integrating the produced near-surface shear wave velocity model with a legacy 2003 P-wave seismic reflection cube, mine mapping and drilling information enabled the investigation of the structural linkage between the near-surface groundwater aquifers and deep mining levels (~ 3 km depth). The faults and dykes mapped at the mining level intersect and cross the near-surface aquifers, thus making these structures possible conduits for water migration to the deep mining levels. The findings of this research illustrate the advantages of integrating shallow and deep subsurface information to constrain the timing of geological structures and mitigate the risks associated with water ingress to the mining levels. The final model produced can be used for future mine development, improving safety and production, and for extending the Life of Mine (LoM).

Velocity models of the shallow (a few hundreds of meters) geology are hardly retrieved from deep seismic reflection exploration data, despite their importance in near-surface characterization, improving seismic mapping resolution at depth, and constraining deeper geological models. In this work, we compute the near-surface shear wave velocity model in the vicinity of South Deep Gold Mine, using surface waves present in the 2D and 3D deep seismic reflection data acquired at the mine. The obtained near-surface model is then used to (1) characterize the near-surface and (2) better constrain possible water conduits (faults, fracture zones and dykes) mapped at mining levels, that enable the migration of water from overlying formations to the mining levels, and (3) constrain the timing of faults and dykes activity in the vicinity of the mine. The analysis is carried-out on reflection seismic data acquired for deep mineral exploration, where the acquisition parameters were not optimized for surface wave techniques, thus the reciprocity principle is used to improve the data density, coverage, and near-surface mapping resolution. The lithostructural information retrieved from the produced pseudo-2D and -3D shear wave velocity models are consistent with information obtained from available borehole data and published records in the study area. Integrating the produced near-surface shear wave velocity model with a legacy 2003 P-wave seismic reflection cube, mine mapping and drilling information enabled the investigation of the structural linkage between the near-surface groundwater aquifers and deep mining levels (~ 3 km depth). The faults and dykes mapped at the mining level intersect and cross the near-surface aquifers, thus making these structures possible conduits for water migration to the deep mining levels. The findings of this research illustrate the advantages of integrating shallow and deep subsurface information to constrain the timing of geological structures and mitigate the risks associated with water ingress to the mining levels. The final model produced can be used for future mine development, improving safety and production, and for extending the Life of Mine (LoM).

Velocity models of the shallow (a few hundreds of meters) geology are hardly retrieved from deep seismic reflection exploration data, despite their importance in near-surface characterization, improving seismic mapping resolution at depth, and constraining deeper geological models. In this work, we compute the near-surface shear wave velocity model in the vicinity of South Deep Gold Mine, using surface waves present in the 2D and 3D deep seismic reflection data acquired at the mine. The obtained near-surface model is then used to (1) characterize the near-surface and (2) better constrain possible water conduits (faults, fracture zones and dykes) mapped at mining levels, that enable the migration of water from overlying formations to the mining levels, and (3) constrain the timing of faults and dykes activity in the vicinity of the mine. The analysis is carried-out on reflection seismic data acquired for deep mineral exploration, where the acquisition parameters were not optimized for surface wave techniques, thus the reciprocity principle is used to improve the data density, coverage, and near-surface mapping resolution. The lithostructural information retrieved from the produced pseudo-2D and -3D shear wave velocity models are consistent with information obtained from available borehole data and published records in the study area. Integrating the produced near-surface shear wave velocity model with a legacy 2003 P-wave seismic reflection cube, mine mapping and drilling information enabled the investigation of the structural linkage between the near-surface groundwater aquifers and deep mining levels (~ 3 km depth). The faults and dykes mapped at the mining level intersect and cross the near-surface aquifers, thus making these structures possible conduits for water migration to the deep mining levels. The findings of this research illustrate the advantages of integrating shallow and deep subsurface information to constrain the timing of geological structures and mitigate the risks associated with water ingress to the mining levels. The final model produced can be used for future mine development, improving safety and production, and for extending the Life of Mine (LoM).

Velocity models of the shallow (a few hundreds of meters) geology are hardly retrieved from deep seismic reflection exploration data, despite their importance in near-surface characterization, improving seismic mapping resolution at depth, and constraining deeper geological models. In this work, we compute the near-surface shear wave velocity model in the vicinity of South Deep Gold Mine, using surface waves present in the 2D and 3D deep seismic reflection data acquired at the mine. The obtained near-surface model is then used to (1) characterize the near-surface and (2) better constrain possible water conduits (faults, fracture zones and dykes) mapped at mining levels, that enable the migration of water from overlying formations to the mining levels, and (3) constrain the timing of faults and dykes activity in the vicinity of the mine. The analysis is carried-out on reflection seismic data acquired for deep mineral exploration, where the acquisition parameters were not optimized for surface wave techniques, thus the reciprocity principle is used to improve the data density, coverage, and near-surface mapping resolution. The lithostructural information retrieved from the produced pseudo-2D and -3D shear wave velocity models are consistent with information obtained from available borehole data and published records in the study area. Integrating the produced near-surface shear wave velocity model with a legacy 2003 P-wave seismic reflection cube, mine mapping and drilling information enabled the investigation of the structural linkage between the near-surface groundwater aquifers and deep mining levels (~ 3 km depth). The faults and dykes mapped at the mining level intersect and cross the near-surface aquifers, thus making these structures possible conduits for water migration to the deep mining levels. The findings of this research illustrate the advantages of integrating shallow and deep subsurface information to constrain the timing of geological structures and mitigate the risks associated with water ingress to the mining levels. The final model produced can be used for future mine development, improving safety and production, and for extending the Life of Mine (LoM).

Velocity models of the shallow (a few hundreds of meters) geology are hardly retrieved from deep seismic reflection exploration data, despite their importance in near-surface characterization, improving seismic mapping resolution at depth, and constraining deeper geological models. In this work, we compute the near-surface shear wave velocity model in the vicinity of South Deep Gold Mine, using surface waves present in the 2D and 3D deep seismic reflection data acquired at the mine. The obtained near-surface model is then used to (1) characterize the near-surface and (2) better constrain possible water conduits (faults, fracture zones and dykes) mapped at mining levels, that enable the migration of water from overlying formations to the mining levels, and (3) constrain the timing of faults and dykes activity in the vicinity of the mine. The analysis is carried-out on reflection seismic data acquired for deep mineral exploration, where the acquisition parameters were not optimized for surface wave techniques, thus the reciprocity principle is used to improve the data density, coverage, and near-surface mapping resolution. The lithostructural information retrieved from the produced pseudo-2D and -3D shear wave velocity models are consistent with information obtained from available borehole data and published records in the study area. Integrating the produced near-surface shear wave velocity model with a legacy 2003 P-wave seismic reflection cube, mine mapping and drilling information enabled the investigation of the structural linkage between the near-surface groundwater aquifers and deep mining levels (~ 3 km depth). The faults and dykes mapped at the mining level intersect and cross the near-surface aquifers, thus making these structures possible conduits for water migration to the deep mining levels. The findings of this research illustrate the advantages of integrating shallow and deep subsurface information to constrain the timing of geological structures and mitigate the risks associated with water ingress to the mining levels. The final model produced can be used for future mine development, improving safety and production, and for extending the Life of Mine (LoM).