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Post-wildfire geological hazards are an emerging problem for a number of different environments, including areas not typically associated with these events such as the Alpine Region. The risk connected with post-fire processes such as debris-flows and flood-type events threatens people, infrastructures, services and economical activities. Apart from a few examples, such as in the USA and Australia, there is a lack of models available to quantify the increase in susceptibility of the aforementioned phenomena as a result of the modification induced by the wildfires. In this work we test the application of a modified version of the RUSLE, on GIS, to quantify the post-fire erosive phenomena for a case study in the north-western Italian Alps. The results of its application, taking advantage of high-resolution rainfall series and data deriving from field surveys, highlight the marked increase (more than 20 times) in erosion rates, quantified by expressing both the EI (erodibility index), the A (monthly soil loss) and the SL (monthly sediment loss) rise. The months of April, May and June represent the larger share of the total quantities. This is a consequence of the noticeable increase of the EI, which for the post-fire scenario is more than one order of magnitude higher than the pre-fire one.

Geopolitical developments since February 2022 and the numerous debates on climate change such as the COP27 are pushing for a greater acceleration in decarbonising the energy sector. The use of geothermal energy for thermal energy production and storage in district heating and cooling (DHC) grids may also be a key element in overcoming short-term energy peaks. This work aimed at evaluating the efficiency and performance of one of the most promising underground thermal energy storage systems, which uses boreholes to store heat or cold (BTES). Numerical simulations allowed for understanding how these technologies can be used as backup systems, or when the energy demand overcomes that supplied by conventional heating systems. The knowledge on how to exploit this energy source shows that a continuous heat extraction from the storage volume can meet both the base and peak load requests for several users, with cumulative energy amounting to 476,000 kWh over the first month. This study proved how the integration of these technologies in DHC contexts can contribute to greater energy and economic savings, becoming an efficient and flexible solution to meet the energy demand from the grid, and also as a backup system.

Carbonate rocks have a widespread diffusion in the Earth crust and are extensively used in cultural heritage and buildings. These rocks can be naturally or anthropically exposed to high temperatures. Consequently, relating physical properties to temperature-induced damage is extremely important. Six sets of compositionally and texturally different carbonate rocks, spanning from limestones and marbles to dolomitic marbles, were analysed in this study. Different physical properties, such as porosity, seismic wave velocities and electrical resistivity, were measured before and after thermal treatments with heating/cooling ranges between 105 and 600°C. Microstructural observations and optical analyses were used to investigate how temperature-induced damage affects the physical measured properties of the different microstructures. This integrated approach allowed to define a generalised relationship between physical properties and thermal-induced damage, by way of an induced damage index valid for a broad suite of carbonate rocks.

A case study on the use of direct and indirect investigations for the effectiveness evaluation of jet-grouting interventions for bridge scour protection is presented. The major concern of this scour countermeasure is that a reliable verification and imaging of the exact dimensions and shape of the grouted elements and their related strength and integrity are difficult to obtain. An integrated cost-effective and slightly invasive approach, by means of indirect surveys, is proposed in this work to limit re-drilling and core sampling of jet columns. Tests are performed on a bridge located in the Province of Cuneo (NW Italy). On site, active fluvial activity was scouring four of the 19 bridge piers and jet-grouting interventions were designed to prevent bridge collapse. A dual approach was consequently applied to evaluate the goodness of jet-grouting treatments: results of direct tests (visual and mechanical characterization of core drillings, with Point Load and Uniaxial Compressive Strength tests) have been compared to indirect investigations (seismic down-hole tests and 2-D cross-hole tomography, laboratory Ultrasonic Pulse Velocity measurements). All the techniques showed potentiality in identifying variations of the jet-grouting properties within the columns. Generally, worsening in jet-grouting properties was coherently identified by a decrease in the seismic velocities and in the mechanical parameters and confirmed by visual inspection of core drillings. Local anomalies and discrepancies between the adopted method were however highlighted and critically discussed as a function of the limitations, disturbances and investigated volumes of each method.

Several soil improving systems are available to increase the geotechnical properties of low resistance soils and increase the stability of overlaying constructions. Most of the already available methods make use of injections of more compacted material inside the ground, like: micro-piles, sand compaction piles, stone columns or grouting. Most of these solutions requires vibrations and rotary drilling, which could compromise soil properties and overlaying building integrity. Recently an innovative soil improving system by injections of a sand/gravel mixture was developed by Novatek® through mechanical preload of the mixture by compression adopting a hydraulic jack. The advantage of this last system with respect to available methods is the absence of vibrations and rotary drilling operations. In this study, the application of this system is documented in a first trial test site in the central Po plain (Italy). Description of the system and of the executed injections are reported. Characteristics of the ground before and after injections are compared, using both geotechnical and geophysical tests, in order to evaluate the system performances, which were also ascertained with direct verification through an explorative trench. The first results reported, even if for limited application depths, highlight the good potentialities of the improving system with respect to the increase of geotechnical parameters in the treated soil.

• Monitoring of hydrothermal fluid emissions can provide detailed information about convective upwelling of geothermal fluids and their geochemical characteristics, as a function of tectonic stress or deeper gas input. In particular, at the Salinelle of Mt. Etna Geosite (Paterno' and Belpasso, Eastern Sicily) natural emissions mainly consist of a fluid phase made of salty water, mud, gas and liquid hydrocarbons from an admixture of magmatic and hydrothermal gases. In this framework, our study mainly focused on the thermal and geochemical monitoring of hydrothermal fluids of the most active site, Salinelle dei Cappuccini. N earby hydrothermal vents (Salinelle del Fiume; Salinelle di San Biagio), were also investigated. Analysis of the magnitude and frequency of seismic events all around Mt. Etna were conducted as well. Analysis of daily temperatures showed a constant trend: higher values (> 35 °C) within the first monitoring period, followed by a strong decrease (down to 9 °C), and a new gradual increase over the following months. This trend seems to be linked to magmatic processes occurring at depth below Mt. Etna, and could lead to a modification of the geochemical and thermal characteristics of the fluid issuing at the mud-pools and gas vents of Salinelle. The higher the frequency of seismic events corresponding to higher daily energy released, the higher fluid temperatures observed.Understanding how these fluids blend and what is their relationship with Mt. Etna volcanism can be of great importance in forecasting new eruptive cycles in the case they precede changes in volcanic activity.

Treatments to reduce the leaching of contaminants (chloride, sulfate, heavy metals) into the environment from bottom ash (BA) are investigated, as a function of the ash&rsquo, s particle size (s). The aim is to make BA suitable for reuse as secondary raw material, in accordance with the legal requirements. Such treatments must be economically feasible and, possibly, have to use by-products of the plant (in this case, steam in excess from the turbine). For the sake of completeness and comparison, carbonation is performed on those BA particle size classes that are not positively responsive to steam washing. BA is partitioned into four different particle size classes (s &ge, 4.75, 4.75 &gt, s &ge, 2, 2 &gt, 1 and s &lt, 1 mm, corresponding to 36, 24, 13 and 27 wt%, respectively). In the case of s &ge, 2 mm (60 wt%), steam washing is effective in reducing to under the legal limits the leaching of chlorides, sulfate and heavy metals (Zn, Cu, Cd, Pb). It has been observed that steam washing causes both removal and dissolution of thin dust adherent to the BA&rsquo, s surface. BA with 2 &gt, 1 (~13 wt% of total BA) requires a combination of steam washing and carbonation to achieve a leaching below the legal limits. The finest BA fraction, s &lt, 1 mm (~27 wt% of total BA), is treated by carbonation, which reduces heavy metals leaching by 85%, but it fails to sufficiently curb chlorides and sulfates.

In the north of Québec (Canada), off-grid aboriginal communities rely on diesel for both space heating and electricity production. Renewable alternatives are therefore necessary to reduce the impact of burning diesel in a region with strong population growth and increasing energy needs. The main challenges are the subarctic environment (more than 8000 heating degree days), the presence of permafrost and the lack of local expertise on drilling and installation of borehole heat exchangers.The communities of Kuujjuaq (58 °N) and Whapmagoostui-Kuujjuarapik (W-K, 55 °N) were chosen as case studies to evaluate the shallow geothermal potential and predict the long-term behaviour of ground source heat pumps (GSHP) and underground thermal energy storage systems (UTES). Local geology mainly consists of low permeable and thermally conductive crystalline bedrock (thermal conductivity of 2-4 W/mK) underlying highly permeable, frost-susceptible and poorly conductive marine sediments (thermal conductivity of 1-1.5 W/mK), generally not thicker than 30-40 m. Electrical resistivity tomography and ground penetrating radar surveys have been carried out to locally evaluate the presence of ice-rich ground that strongly depends on the local hydrogeological conditions. Average underground temperature in the first 100 m is around 1 °C in Kuujjuaq and 2 °C in W-K. Geothermal gradient and heat flux were estimated to be on average 15 °C/km and 40 mW/m2, respectively.Results of the studies carried out in these villages show that both GSHP and UTES are viable technologies to replace part of the current diesel consumption of residential buildings and drinking water facilities, with 10% to 50% primary energy saving depending on the technology. Fifty years’ life-cycle cost analyses demonstrated that the levelized cost of energy for GSHP and UTES is as low as 0.10 and 0.19 USD$/kWh, respectively, compared to the business-as-usual scenario standing at 0.21 USD$/kWh. It also turned out that the energy and drilling costs are key obstacles to a widespread deployment of these technologies in the North. A cost of 110 USD$/m has been defined as a threshold for getting interesting paybacks on the initial financial investment. UTES is also a valuable technology aiming to extend the growing season of community greenhouses in place in both Kuujjuaq and W-K. In Kuujjuaq, a coupled daily and seasonal heat storage is under study to provide renewable heat and help increase the food security in Nunavik.Future activities aim at the set-up of a first demonstration plant to be tested in a subarctic environment with underground close to permafrost conditions. A 200-m well will be drilled in 2020 in W-K and the installation of a borehole heat exchanger will be showcased for technological transfer. Conventional thermal response tests (TRT) and a novel approach of oscillatory TRT will also be carried out to evaluate the in-situ thermal conductivity and heat capacity.

Burial mounds are artificially (or partially artificially) erected hills that cover a monumental tomb, usually in the form of a stone chamber. Different types of burial mounds are distributed worldwide and have built in different archaeologically interesting periods. Use of non destructive geophysical surveys for their study offer the opportunity to image their internal structure and evidence peculiar anomalies that can be later investigated with archaeological excavations, limiting invasiveness. The main innovative part of this work lies on the combined use of Ground Penetrating Radar and Electric Resitivity Tomography over and inside an unexplored burial site in Japan, the Tobiotsuka Kofun, a late Kofun period burial mound, dated approximately late 6th-early 7th century CE and located in the Okayama Prefecture. Effectiveness of the geophysical surveys is demonstrated by the correct imaging of known structures and by the combined evidence of the mound organization, which allowed to draw a reliable initial archaeological interpretation with evidence of several interesting excavation spots. The adopted methodological surveying approach was verified as a valuable choice for investigations in similar archaeological settings.

Underground Thermal Energy Storage systems have showed to be a useful and increasing technical solution for covering heating and cooling and domestic hot water buildings' demand. Thermal influence of these plants is however not still debated as it deserves and correct monitoring strategies appear to be of major importance both to better understand processes and to highlight their environmental effects into high populated areas. Litho-, hydro- and bio-sphere can indeed be adversely affected by temperature variations induced in the underground by heat storage applications. For this purpose, a geophysical monitoring approach using time-lapse electrical resistivity measurements contemporary to analogical simulations is here tested at laboratory scale. Results of the experiments are reported comparing measured apparent resistivity with direct temperature measurements and numerical simulations of heat propagation. Data presented confirmed that electrical resistivity has powerful relation with temperature variation in monitored media. In addition, they showed that also without performing data inversion valid temperature estimation can be carried out. Post-processing calibration of apparent resistivity data showed to be in acceptable agreement with both temperature measurements and numerical simulations. Simple apparent electrical resistivity variations appear therefore to be a promising, economic, quick and non-invasive tool for mapping thermal modifications induced in the underground by shallow geothermal applications.

A comparative study was carried out aiming at characterizing the thermal conductivity of rocks sampled in a borehole heat exchanger field. Twenty-three samples were analysed with four different methods based on both steady-state and transient approaches: transient divided bar (TDB), transient line source (TLS), optical scanning (OS), and guarded hot plate (GHP). Moreover, mineral composition (from XRD analyses), P-wave velocity, and density were investigated to assess the petro-physical heterogeneity and to investigate possible causes of divergence between the methods. The results of thermal conductivity showed that TLS systematically underestimates thermal conductivity on rock samples by 10–30% compared to the other devices. The differences between TDB and OS, and GHP and OS are smaller (about 6% and 10%, respectively). The average deviation between TDB and GHP, for which the specimen preparation and the measurement procedure were similar, is about 10%. In general, the differences are ascribable to sample preparation, heterogeneity and anisotropy of the rocks, and contact thermal resistance, rather than the intrinsic accuracy of the device. In case of good-quality and homogeneous samples, uncertainty can be as low as 5%, but, due to the above-mentioned factors, usually uncertainty is as large as 10%. Opposite relationships between thermal conductivity and P-wave velocity were observed when analysing parallel and perpendicular to the main rock foliation. Perpendicular conductivity values grow with increasing perpendicular sonic velocity, while parallel values exhibit an inverse trend. Thermal conductivity also appears to be inversely correlated to density. In quartz-rich samples, high thermal conductivity and low density were observed. In samples with calcite or other likely dense mineral phases, we noticed that lower thermal conductivity corresponds to higher density. The presence of micas is likely to mask major differences between silicate and carbonate samples.

The effect of high temperatures as a degrading factor of rock materials is investigated in this study. Valdieri Marble samples, collected in a quarry in North-western Italian Alps, were subjected to thermal cycles (ranging from 105° to 600 °C) and to subsequent non-destructive and destructive laboratory tests with the aim of evaluating the variation of physical and mechanical properties as a function of temperature variations. Physical and mechanical measurements were complemented with microscopic observations on thin sections. The increase of crack density with temperature and the consequent porosity increases were found to be the main causes of degradation of physical and mechanical properties. In general, density, ultrasonic pulse velocity, wet electrical resistivity, uniaxial compressive strength and Young's moduli decrease as temperature increases. By contrast, peak strain and porosity increase. Correlations between temperature and physical-mechanical properties were proposed and compared to other relationships already established in scientific literature. A damage parameter to quantify the degradation of mechanical properties with temperature is also proposed.

The aim of this study is twofold: (i) characterization of the bottom ashes from the Incinerator plant of the city of Turin (northern Italy), in terms of their chemical/phase compositions and capacity to release heavy metals in leachates, as a function of particle size; (ii) investigation of thermal treatments' efficacy to promote inertization of the same bottom ashes, exploring time-temperature ranges with t ≤ 6 h and T ≤ 1000 °C. Special attention is paid to macro-sampling techniques in order to have samples that are representative of the average bottom ashes production. Micro-XRF, ICP-OES, SEM-EDS, Ion Chromatography and X-ray powder diffraction were used to investigate bottom ashes and leachates. Bottom ashes are mainly constituted by an amorphous phase, ∼66-97 wt%, regardless of particle size; the remaining phases are quartz, calcite, Fe-oxides, melilite and other minor crystalline materials. The amorphous phase exhibits a relevant dependence on particle size, and undergoes dissolution in water up to 20 wt%, thus being the most important component in affecting chemical species release. The smaller the bottom ashes' particle size, the more the heavy metals (major species: Zn, Cu, Ti, Pb) and calcium contents increase, whereas silicon's decreases. Electrolytic current observations in combination with phase/chemical composition and metals release as a function of particle size, suggest that bottom ashes partition into two classes, i.e. ≥1 and1 mm, for inertization purposes. Thermal treatments exhibit partial efficacy to curb heavy metals mobility: whilst they reduce Cu release, they lead to a inverse effect in the case of Cr.

The seasonal storage of thermal energy in the ground is a useful application able to provide H&C and DHW demand of commercial or residential buildings. Several examples in Canada and Northern Europe demonstrated the reliability and convenience of these systems in terms of both energy and economic savings, but more demonstration sites are however necessary. The surrounding litho-, hydro- and bio-sphere are influenced by the plant's activity and a trustworthy supervision of the temperature field would bring advantages to both the environment and the system's efficiency. Usually numerical modeling is used to forecast the system behavior but results of simulations can be strongly dependent from assumed material characteristics and should be strictly calibrated on real data. To better understand thermal processes in the ground related to thermal injection and thermal storage, a field scale BTES living lab was build up nearby Torino (Northern Italy) within unsaturated alluvial deposits. Results show that approximately 9.1 GJ were transferred to the ground during the first year, raising the undisturbed temperature by 2 °C, and that a correct comparison of monitoring data and numerical simulations can be obtained following a specific site characterization.

In many cases it is observed that drains or piezometers used in hydrogeology or landslide mitigation, often at considerable cost, may partly or wholly lose their function—even in few months—due to phenomena such as scaling, fouling, corrosion, etc. Several techniques are already available to overcome these problems, but none has proved decisive and/or effective in every situation. The use of ultrasonic technology in this context has certainly highlighted the complexity of the physical and chemical phenomena that characterize these kinds of problems. Analyzing the results obtained from tens of laboratory tests, it was noted that several factors play a role, and that such factors can somehow influence the effect of ultrasonic waves in removing fouling. However, it was highlighted that, for small diameter drainage (

Gold, among all conventional metals subject to a progressive increase in value in the international market, has jumped powerfully into the spotlight during all economic crises. This contingency led to reconsider the dismissing process of some Italian mining sites and in particular at Pestarena- in the Anzasca Valley near Macugnaga (NW Alps) -the most important historical gold mine in the Alps. This mine site interests an area of 4 km2 through about 40 km of tunnels. The orebodies are composed of gold-bearing post-metamorphic structures, represented by mineralized cataclasites and veins, often discontinuous and with complex structural geometry. Such a structural complexity makes it difficult to assume a profitable method of exploitation without a whole prospection of the deposit, pursuing the goals of safety and sustainability of the mine. In order to visualize the geometric relationships between orebodies and mine levels, it was necessary to digitalize the unique still existing mining plan, updated at the end of 1960 when the mine was closed. This process led to the creation of a 3D digital map. This has proven critical in the understanding of spatial relationships between surface topography and mine elements. The study allowed us to plan further field surveys based on new criteria that gave a better geo-mining knowledge of the site. It also demonstrates a potential interest for the exploitation of immediately exploitable gold resources and give interesting highlights on the possible future development of the mine activities.

A Borehole Thermal Energy Storage living lab was built up nearby Torino (Northern Italy). This living lab aims at testing the ability of the alluvial deposits of the north-western Po Plain to store the thermal energy collected by solar thermal panels and the efficiency of energy storage systems in this climatic context. Different monitoring approaches have been tested and analyzed since the start of the thermal injection in April 2014. Underground temperature monitoring is constantly undertaken by means of several temperature sensors located along the borehole heat exchangers and within the hydraulic circuit. Nevertheless, this can provide only pointwise information about underground temperature distribution. For this reason, a geophysical approach is proposed in order to image the thermally affected zone (TAZ) caused by the heat injection: surface electrical resistivity measurements were carried out with this purpose. In the present paper, results of time-lapse acquisitions during a heating day are reported with the aim of imaging the thermal plume evolution within the subsoil. Resistivity data, calibrated on local temperature measurements, have shown their potentiality in imaging the heated plume of the system and depicting its evolution throughout the day. Different types of data processing were adopted in order to face issues mainly related to a highly urbanized environment. The use of apparent resistivity proved to be in valid agreement with the results of different inversion approaches. The inversion processes did not significantly improve the qualitative and quantitative TAZ imaging in comparison to the pseudo-sections. This suggested the usefulness of apparent resistivity data alone for a rough monitoring of TAZ in this kind of applications.

In the context of shallow geothermal applications, geo¬physics can be applied as a design and monitoring tool. One of the most referred applications is monitoring and imaging the time lapse evolution of the Thermal Affected Zone (TAZ). In the last few decades electrical resis¬tivity measurements have been adopted both for the char¬acterization and to image spatial and temporal distribution of temperature within the ground. This paper is therefore devoted to the use of electrical resistivity in this context with a focus on the Italian state of the art. A brief literature review of thermal characteristics influencing the resistivity value and example applications of Electric Resistivity Tomography (ERT) data is reported. Two example case histories, in very different hydrogeological contexts in northern Italy, are also presented.

International audience; In the Northern Apennines there are many historical villages and castles, which are of great value and represent a cultural heritage of great importance. Their presence within a territory greatly affected by landslide hazards creates, in many circumstances, the need to solve problems of land management and to act for the preservation of historical monuments. This paper describe an interesting landslide, failed during the night of 28 February 2004, that involved the village of Rossena: the failure damaged the village (Fig. 1), the road and the fields down to the stream but, fortunately, the castle just upslope the village was not involved at all. The 10th century massive castle of Rossena stands on the top of a cliff at about 500 m a.s.l., on the border between the provinces of Parma and Reggio Emilia, and it is surrounded by a small ancient village. The castle of Rossena is the best preserved stronghold of the Longobard times, enlarged and reinforced in the tenth century and partially rebuilt by Bonifacio, the father of Matilda of Canossa (the Vice-Queen of Italy and probably the most important woman in the Middle Ages) as a defensive structure guarding the Enza Valley. In addition, at Conossa, very close to Rossena, there was the meeting between Pope Gregory VII and the Emperor of Germany Henry IV, during the historical event known as "fight for the investitures". For these reasons, the area of Rossena is one of the most relevant from a historical point of view in the entire western part of the Emilia Romagna Region and it also has a high value as a geosite (Coratza et al., 2004).

In the hilly area of Langa, which is situated to the south of the city of Alba between the Belbo and Bormida Valleys, the heavy rainfall and subsequent floods of 3-6 November 1994 triggered numerous landslides. The slides caused serious damage to residential areas and various types of infrastructure. Engineering geological, geomorphological, geotechnical, hydrogeological, and geophysical methods were applied to investigate the instabilities. Among hundreds of failures, most of them were planar slides and debris-mud flows. However, the numerous landslides directly connected to the event represent only a part of the large and varied types of phenomenon in this area. In fact, most of the recent landslides can be considered as reactivated older ones that were more-or-less quiescent. They intersect at the depth the marly basement and are directly connected to the recent geological and tectonic evolution of the area. The paper describes the mass movements and their causative factors. It also focuses on the hazards and risks associated with the instabilities, and their mitigation measures.