Italian journal of engineering geology and environment

Landslide monitoring at both large and detailed scales using satellite A-DInSAR in Southern Lazio (italy)

Tue, 25 Jun 2024 00:00:00 +0000

The specific aim of this work has been exploiting satellite Advanced Differential SAR Interferometry (A-DInSAR) big data through the implementation of methodologies that can provide new insights into the identification of unknown landslides and the update of the inventoried landslides, at two different levels of detail: regional and slope scales. In particular, the slopescale studies are aimed at investigating the landslide processes that pose the greater risk of interfering with roads and inhabited zones, using both multisource A-DInSAR velocity measurements, geomorphological evidence, and surveys of damage to buildings or infrastructure. This multiparametric evaluation allows the update of the state and styles of activity and the landslide perimeters. In this paper, we provide a general overview of the method that works for regional scale analysis, with a focus on 3 case studies located in the Frosinone province (Central Italy), that have been investigated at a slope scale. Such cases concern slow-moving landslides such as complex, slow flow, or roto-translation mechanisms, featured by shallow or moderate depth and extension. The presented results pointed out that A-DInSAR big data can provide an update of the state of knowledge of active slope movements at a regional scale and can drive detailed studies with high-resolution data and onsite surveys to assess the hazard scenarios.

A swift approach for identifying vulnerable linear transport infrastructures in areas prone to floods and erosion

Claudio Arras, Mara Calia, Stefania Da Pelo, Mauro Coni, Francesca Maltinti — Tue, 25 Jun 2024 00:00:00 +0000

Linear transport infrastructures are essential for the socioeconomic development of industrialized countries. However, adverse meteorological and hydrogeological events can result in significant economic losses. Globally, floods have the most substantial socio-economic impact. Climate Change, due to the extent of transport infrastructures over flood-prone territories, is a very important factor in worsening flood risk. The main objective of this study is to identify the sections of the hydrographic network that are susceptible to flood and erosion hazards where road infrastructures are located. The Metropolitan City of Cagliari (Sardinia, Italy) is selected as test site, due to the presence of several coastal watersheds and of a high population density. A swift methodological approach, based on already available datasets from public repositories and GIS analyses, is presented. This approach includes: i) geomorphological characterization of the hydrographic network; ii) census of stream tracts where bridges were damaged in past flood events; iii) identification of potentially critical tracts (PCT), based on similar geomorphological conditions; iv) multi-temporal satellite imagery analysis of PCT for the identification of flood-prone areas and, therefore, vulnerable road crossings. The adopted methodology has proved to be effective for the identification of vulnerable road crossings over wide portion of territories, identifying critical sites that need further investigation.

Assessing local seismic response in major-hazard industrial plants: implications for natech events

Tue, 25 Jun 2024 00:00:00 +0000

Seismic events can trigger a NaTech disaster, leading to the release of hazardous materials, fires, and explosions. These can occur within industrial complexes and along distribution networks as a result of natural disasters. Industrial plants, composed of structural and non-structural components, may be damaged when subjected to earthquakes of a given magnitude. Some examples of these disasters occurred in Kobe (1995), Kocaeli (1999), and Tohoku (2011). This study aims to assess the local seismic hazard by the implementation of different analytical approaches in a Major-Hazard Industrial Plant (MHI P) triggering a NaTech event. For the Bussi MHI P area, a geodatabase has been designed where geometric and geotechnical parameters have been associated with each geotechnical unit. The local seismic hazard has been simulated using 1D and 2D codes, considering two seismic hazard scenarios limit state SLV - SLC according to the National Building Code (NTC2018). In this study, the amplification factor AF has been calculated within the natural vibration range of an H2O2 storage tank located in the Bussi MHI P facility. This type of structure was chosen as it represents an element able to generate a relevant accident and consequently, a potential NaTech event.

Numerical simulation on the groundwater contamination evolution in industrial settings

Tue, 25 Jun 2024 00:00:00 +0000

The hydrogeological numerical simulation represents a tool for the protection of aquifers and for modeling the groundwater flow and transport. This study aims to build numerical models of a porous aquifer located in the alluvial plain of Catania (eastern Sicily, Italy), to evaluate groundwater flow and hypothetical contamination plume trends, even in interaction with pumping activity. To implement the flow and transport simulations, geological and hydrogeological conceptual models were defined using borehole and well data. The studied aquifer is semi-confined, with the presence of alluvial sediments mixed with sandy clays and silts. Because of the presence of anthropic activities in the area, the accidental spill of a contaminant would represent a social problem in the frame of the environmental and health risk. In this regard, we carried out numerical simulations that consider the hydrodynamic parameters of the aquifer, the contaminant concentration, and the presence of pumping wells. The model shows that groundwater flow is directed towards east, and that the presence of wells locally affects it. The transport model shows that a hypothetical dissolved contamination plume mainly follows the groundwater flow path, and that the presence of pumping well accelerates its flow towards elements at risk.

Engineering-geological insights into the gypsum-bearing deposits of Punta delle Pietre nere (Puglia Region, Italy)

Tue, 25 Jun 2024 00:00:00 +0000

In a very limited area near Punta delle Pietre Nere (Puglia region, Italy), chalky deposits crop out along with black limestones interspersed with bituminous marls and igneous rocks. From 1927 to 1930 these gypsums were affected by some works that modified the path of the Acquarotta Canal to connect the close lagoon (Lesina Lake) to the sea and facilitate its flow conditions. Over time, the strip of land close to the Acquarotta Canal was affected by sinkhole phenomena related to the dissolution of the chalk. These phenomena also occurred in the nearby town of Lesina Marina. Since 1990, numerous investigations have been carried out in the area, including geological, hydrogeological and geomechanical surveys, geo-electrical and seismic surveys, and remote sensing analyses. In this study, we present the results of recent site-specific investigations, which enabled to better understand the buried limits of the chalky deposits, their depth, the geological characteristics of the covering soils and the groundwater flow conditions. In summary, the distribution of gypsum-bearing deposits in the subsoil of the area is now better defined than in the past, when the uncertainty of the data represented a factor strongly limiting the local possibilities of settlements’ development.

Direct and indirect prospecting to detect and characterise sinkhole features in urban evaporitic environments

Chiara Calligaris, Alice Busetti, Emanuele Forte, Chiara Piano, Luca Zini — Tue, 25 Jun 2024 00:00:00 +0000

Natural subsidence sinkholes (according to Gutiérrez et alii, 2008, 2014; Parise 2019, 2022), both in carbonates and evaporites, represent a severe threat to man-made structures. Especially when bedrock is mantled and in urban areas, the identification and characterization of these phenomena is always challenging. For this reason, multidisciplinary and multi-technique approaches are recommended and in detail, the integrated use of geophysical techniques (Electrical Resistivity Tomography, Reflection and Refraction Seismic, Electromagnetometers and 2D Ground Penetrating Radar - GPR) and most recently developed 3D GPR is strongly suggested. Thanks to the Agreements signed between the University of Trieste and the Geological survey of the Friuli Venezia Giulia Region (NE Italy), since 2007 the researchers approached these issues in specific test site areas. From the studies in urban mantled evaporitic bedrock areas, emerged the supremacy of the 3D GPR jointly with reflection seismic, being the former able to identify with high accuracy and detail shallow deformations, and the latter the best approach to identify the thickness of cover materials, the morphology of the bedrock and the sinkhole location.

By-pass sediment system to replace longshore current in harbour areas

Tue, 25 Jun 2024 00:00:00 +0000

This paper is part of the results achieved in Tech4You project T4Y S2G2PP2 funded by PNRR (Piano Nazionale di Ricerca e Resilienza). The Tech4You project focused on the silting process affecting the Cetraro harbour mouth (Calabria, southern Italy). The study area is located along the northern Calabrian Tyrrhenian coast and is part of a physiographic unit with a west-southwest fetch greater than 1650 km. The wave climate is characterised by a significant wave height of 0.65m (average period of 5.15s) and 1.01 m (average period of 5.7s) offshore and inshore, respectively. The longshore flow of sediments (about 80,000 m3/yr), moving from north to south, is interrupted by the harbour pier producing silting (~10,000 m3/yr sediment deposited at the harbour mouth), and heavy coastal erosion in the down-drift sector. The sediment production in the Aron River catchment (representing the main sediment feed in the physiographic unit) by Gravrilovic model was also studied, with detailed analysis of soil use through multispectral analysis, and estimate an average volume of ~30,000 m3/yr. A bypass system was designed, consisting of a submerged pump installed at the end
of the pier on the up-drift side of the harbour, to replace the original longshore current, contrasting simultaneously both mouth silting and erosion processes in the down-drift coastline.

Analysis and modelling of the September 2022 flooding event in the Misa Basin

Monica Corti, Mirko Francioni, Andrea Abbate, Monica Papini, Laura Longoni — Tue, 25 Jun 2024 00:00:00 +0000

Natural hazard is recognized to be a threat to human society that is becoming more critical under the perspective of climate change. Italy is one of the most exposed European countries to hydrogeomorphological hazard, as proven by the annual casualties and economic losses. Among the most recent events, the one happened in the Misa river catchment in 2022 is of particular interest for the great amount of rainfall poured in just one night, which led to extensive erosion. The mountainous part of the catchment was hit by several landslides, and the resulting sediments and debris, transported downstream by rivers, increased the amount of damages. This event was interpreted as directly caused by climate change, as it was linked to a tropical storm not common at this latitude. This work proposes an analysis of this exceptional event from a hydrological point of view. The 2022 event was compared with other relevant events from the past, in order to evaluate the peak discharge, the sediment erosion and transport processes in the area for different scenarios. The analysis included the modelling at catchment scale with two physically-based models: SWAT, which provides results on channel processes, and SMART-SED, working at the catchment scale. The two scales of analysis, together with field surveys, gave a better understanding of the evolution of the shallow processes during the events. Finally, this work intends to highlight the relevance of hydrological modelling for the management of hazard in different scenarios at catchment scale.

Slope response to effective rainfall of a large, complex rock-slide in flysch material

Tue, 25 Jun 2024 00:00:00 +0000

The Camugnano landslide, located in the Province of Bologna, affects an area of 9.1×105 m2. It is considered a complex phenomenon involving both roto-translational kinematics within the Camugnano Formation’s arenaceous flysch and translational slides that affect the degraded products of the flysch and other clay materials in the lower sector of the unstable slope. The activity of the landslide is characterized by very slow displacement rates (4 cm/year), with occasional acceleration events in the past. The most recent significant event occurred in 2014. In response, various surveys and monitoring activities were conducted, including the use of boreholes, geophysical surveys, displacement measurements through inclinometers, Ground Navigation Satellite System (GNSS), and Robotic Total Station (RTS), and groundwater monitoring through pressure transducers installed in piezometers. The aim of this note is to summarize the monitoring results and compare them with the trend of effective rainfall over multiple years. To determine effective precipitation, the Thornthwaite formulation was used, based on mean daily temperature and daily cumulative rainfall data from the Diga del Brasimone gauge station, located approximately 5 km from the landslide site. The inclinometer monitoring helped identify the sliding surfaces and obtain time series data by integrating displacements on these surfaces. GNSS campaigns conducted periodically revealed displacement rates ranging from 30 to 70 mm/year, generally decreasing progressively from 2014 to 2022. RTS monitoring indicated slow but detectable movements within the landslide. Then comparing GNSS displacements with precipitation data, it was found that displacement rates remained relatively constant regardless of variations in effective precipitation. This trend was also observed when analysing inclinometer data. The groundwater monitoring showed seasonal fluctuations, with peak levels occurring during the winter period in most piezometers. However, no long-term groundwater trend was observed. The displacement record highlights a variable sensitivity of the slope to effective rainfall with respect to the last major reactivation event. Temporary, localized accelerations are in fact recorded after 2014, gradually decreasing in magnitude in the next years. These findings suggest that mitigation strategies could by modified according to this style of activity and indicate that assumptions linking rainy or dry periods to variations in movement acceleration or deceleration may be overly simplistic.

Hydraulic conductivity estimation through the use of tracers tests and geomechanical survey: preliminary outcomes from the Montagna dei Fiori carbonate aquifer (Central Italy)

Tue, 25 Jun 2024 00:00:00 +0000

Nowadays, groundwater is the most important resource on our planet. However, due to population growth, urbanisation, and climate change, this resource is often overexploited or contaminated. In this context, carbonate aquifers provide drinking water to approximately 25% of the global population. Due to aquifers heterogeneities and anisotropic fracture systems, they can be affected by potential contamination and their optimal exploitation represents a challenge aspect. In this particular scenario, carbonate mountain aquifers encompass valuable groundwater resources due to their high recharge rates and excellent water quality; therefore, the understanding of their hydrogeological characteristics are vital for aquifers protection and water management. A valid solution to explore water movement within such aquifers and to quantify the groundwater amount can be offered using artificial tracers. At the same time, the geomechanical surveys can deep the knowledge on fracture density and orientation, providing valuable insights about fracture connection and conductivity. This study combines the advantages of six artificial tracer tests performed in four deep wells (260-500 m b.g.l.) and a geomechanical survey used, among other, to estimate hydraulic conductivity of a mountainous carbonate aquifer located in Central Italy. The results obtained by different methods highlighted the presence of multiple layers with higher conductivity values, able to sustain the groundwater flow without significant piezometric level drawdown during water pumping operations. This approach provides an effective support to the water management company operating.

Investigations using CSIRO HI Triaxial Cells for measuring the stress states of rock masses subject to mining extraction: numerical modelling of in-situ extracted core samples

Tue, 25 Jun 2024 00:00:00 +0000

The measurement of the stress state of rock, carried out insitu using the overcoring CSIRO HI Cell technique, provides valuable information about the rock mass geo-structural and stress conditions. This is particularly useful for calibrating the numerical model of natural slopes and excavations fronts and for assessing their static conditions. Thus, it allows to improve workplace safety conditions in both open-pit and underground quarries. During an in-situ CSIRO test, the stress release strains are measured by 12 strain gauges differently oriented in the space and the stress tensor and the material elastic parameters are then computed. The classic interpretative procedure of stress release test refers to analytical formulations that assume an extracted sample of regular cylindrical shape. However, during overcoring, it may happen that a discontinuity is intercepted, causing the extracted core to break and to assume an irregular shape. To address this challenge, in this work, a Finite Element numerical simulation of stress release was conducted basing on a 3D digital model of the irregular sample resulting from a Photogrammetric Survey. This allowed for the computation of the stress tensor for both irregularly shaped and ideal cylindrical samples. The research proceeded as it follows: i) three-dimensional modelling of the irregularly shaped core using Photogrammetric Techniques and Mesh Editing, which enabled the accurate representation of complex geometries; ii) numerical Modelling of the irregularly shaped core containing the CSIRO HI Cell through Finite Element Analysis, providing insights about stress and deformation distributions; iii) stress State of the rock calculation using a Multiple Linear Regression Procedure by using the coefficient matrix as determined by the core numerical modelling. The implementation of this procedure may facilitate the determination of stress state for irregularly shaped cores, and it enhances to understand how shape and rock elastic properties may influence the stress release behaviour. This comprehensive approach could allow to address challenges associated to stress assessment for irregular shaped rock cores and to improve the accuracy and applicability of geotechnical engineering methods.

Multi-temporal analysis of the geomorphic evolution of the failure surface of the Vajont Landslide

Davide Donati, Alessandro Lambertini, Doug Stead, Monica Ghirotti, Lisa Borgatti — Tue, 25 Jun 2024 00:00:00 +0000

Landslides are among the most common type of hazard that affect mountainous regions. While the impact of the single landslide is often localized and limited to the influence area, in some cases, the occurrence of major events can result in significant and long-lasting social, economic, and environmental impacts that extend beyond the area directly affected by the event. These major landslides involve the sudden detachment of large volumes of rock mass and cause significant disturbance of in-situ stress field due to slope debuttressing and reduction in lateral support, which often result in conditions of limit equilibrium affecting the remaining part of the slope. Effects of such limit equilibrium conditions can range from a long term, gradual morphological evolution of the slope due to progressive detachment of material, to the development of multistage landslides, involving the failure of volumes of rock mass
similar in magnitude and impacts to the original event. In this work, we investigate the post-failure morphological evolution of the daylighting rupture surface and deposit of one of the most important historical landslides, the 1963 Vajont Slide. A preliminary investigation of a pair of airborne laser scanner (ALS) datasets, collected in 2017 and 2023, is undertaken to assess and compute the change in elevation across selected areas within the rupture surface. Based on a three-dimensional change detection analysis, the observed volumetric changes of selected, inferred rockfall events are estimated. Terrestrial and airborne photographs are also used to identify the unstable volumes that have progressively detached, as well as the damage features that outlined these unstable blocks. Finally, we discuss the long-term evolution of the slope with focus on progressive damage accumulation and its spatial relationship with inherited, tectonic structures. Ultimately, this contribution is intended to highlight the important role of post-slope failure damage accumulation on the long-term stability of rock slopes, emphasizing the critical role that post-failure monitoring and analysis can play in outlining the residual landslide hazard and, in some instances, the potential development of multi-stage landslides.

Engineering-geological modelling as a tool for archaeological site preservation strategies

Tue, 25 Jun 2024 00:00:00 +0000

Traditionally, cultural heritage (CH) site conservation strategies have mostly focused on the employment of procedures to protect archaeological exhibits from weathering processes. However, CH-sites are often located in areas affected by geological hazards, which can threaten the conservation of the site itself. For these cases, engineering-geological modelling is an essential tool to design conservation strategies for geohazards management in the framework of CH-site preservation. The research here proposed is focused on the Punta Eolo promontory at Ventotene island (Italy) where the remnant of the roman “Villa Giulia” emperor palace is hosted. Detailed engineering-geological surveying has been carried out at Punta Eolo. In particular, engineering-geological investigations have been coupled with remote investigation of the area of interest. Thanks to the engineering-geological surveys, a detailed engineering-geological map was drafted, also highlighting the geomechanical setting of the Parata Grande Tuff formation (hereinafter, PGT). The presence of a superficial deposit, mainly composed of archaeological material overlaying a tuffaceous unit, was evidenced. To bound this layer’s thickness more effectively, 52 single-station seismic noise measurements were carried out. Seismic ambient noise measurements show significant horizontal-to-vertical spectral ratio (HVSR) resonance peaks at 3 Hz, a variable secondary peak ranging from 9 to 19 14 Hz, respectively related with the contact between the PGT and the underlying lavas and the superficial deposits and PGT units. The measurements conducted at the edge of the promontory show evidence of polarization of the particle motion potentially related to the vibrational behavior of the unstable rock blocks that bound all the site. A 3D model of the cliff, reconstructed by drone photogrammetry technique, allowed to perform the rock mass joints surveying along the not-accessible cliff faces, as well as to visualize the superficial deposits thickness all around the perimeter of the promontory. Additionally, a 3D geological model was made using the RockWorks 16 program to facilitate a more direct visualization of site-specific features. The engineering-geological model here presented enables the development of an efficient conservation strategy for the Villa Giulia archeological site, as a critical tool for mitigating geological risks. Furthermore, future archaeological excavation will be driven by the reconstructed geological model of Punta Eolo.

Integrity of fine-grained layers to DNAPL migration in multilayered aquifers: assessment in a pce-contaminated alluvial system, using high-precision simulations

Alessandra Feo, Riccardo Pinardi, Andrea Artoni, Fulvio Celico — Tue, 25 Jun 2024 00:00:00 +0000

Chlorinated organic compounds widely contaminate aquifer systems worldwide (Doherty, 2000). They belong to the so-called DNAPLs (dense non-aqueous phase liquids), are denser than water, and have very low water solubility. Thus, they can migrate under pressure and gravity forces through the unsaturated and saturated porous medium until they reach a bottom aquiclude (Mercer & Cohen, 1990). They are usually detected in industrial and urban areas, persist in the environment, and are linked to toxic effects. The behavior of chlorinated organic compounds in the subsurface has been studied since the early 1980s, e.g., (Parker et alii, 1987; Kueper et alii, 1989). Some numerical models, including migration and remediation of alluvial aquifers (Guadano et alii, 2022), using the MT3DMS numerical code (Zhou et alii, 2023; Zheng & Wang, 1999), have been written to simulate their migration in aquifer systems. The dynamics of a spilled DNAPL migration in a variably saturated zone can be described using numerical simulations for the governing equations of immiscible phase fluid flow in a porous medium. These are coupled with conserved partial differential equations for each fluid flow, based on the Darcy equation, together with the conservation of mass and an equation of state. They are written as a function of each fluid flow’s saturation, capillary pressure, density, viscosity, permeability, and porosity. Since each phase’s capillary pressure and permeability are a function of the saturation, these equations are non-linear, with a dominant hyperbolic advection term proportional to gravity and the pressure gradient. It is responsible for forming sharp (shocks) front and rarefaction, which can create significant errors in the output results if not treated with conservative numerical solutions methods. The present study deals with the three-dimensional (3D) numerical model implemented to analyze the expected impact of perchloroethylene (PCE) releases in multilayered aquifer systems characterized by the juxtaposition of more permeable layers (gravel and sand) with low-permeability layers (silt and clay). A 3D numerical model is developed using the numerical code CactusHydro, introduced in (Feo & Celico, 2021; Feo & Celico, 2022). It is based on the high-resolution shock-capturing flux (HRSC) conservative method to follow sharp discontinuities accurately and temporal dynamics of a three-phase immiscible fluid flow in a porous medium. CactusHydro resolves the governing equations that describe the migration of an immiscible phase fluid flow in a porous medium composed of non-aqueous (n), water (w), and air (a), and a variably saturated zone. The migration of the spilled DNAPL is considered immiscible, and the effects of the volatilization, biodegradation, or dissolution are not considered. CactusHydro treats the vertical and horizontal movement of the contaminant in the variably saturated zone as a whole and is numerically resolved as a unique zone (not separating the vertical movement from the horizontal one since the flow equation includes both zones). The model presented here simulates the DNAPL migration with the aim of predicting (i) the free-product distribution in multilayered aquifers (up to several hundred meters thick) and then (ii) the distribution of possible long-term pollution sources for shallow and deep groundwaters. A first scenario was simulated in detail, with the scope of understanding whether the interposition of a low-permeability layer between two higher permeability horizons can influence the vertical migration of DNAPLs. The test site is the alluvial aquifer of Parma Plain (Northern Italy), where perchloroethylene (PCE) was recently detected in groundwater (Zanini et alii, 2019; Zanini et alii, 2021), therefore suggesting the existence of DNAPLs sources. The results demonstrated that the PCE can migrate downward through low-permeability layers, even though a very low velocity was estimated.

From survey to analysis and visualization methods, new approaches to define rockfall hazard

Tue, 25 Jun 2024 00:00:00 +0000

Rockfalls are among the most dangerous natural hazards. The study of these phenomena may be complex in relation to the geology and the rock mass characteristics. Recent advances on the use of remote sensing techniques made the survey of rock slopes easier and faster, increasing the amount and quality of data. At the same time, the improved availability of software for characterizing rock slopes and simulating rockfalls permits a more detailed and precise definition of rockfall hazard areas. In this context, this research highlights the importance of using remote sensing techniques in the study of these phenomena, especially in developing accurate and reliable geological and structural models. The Regional Park of Monte Conero (Ancona, Italy) is used as the case example. The study area has been investigated through conventional geological/structural surveys, UAV photogrammetry and iPad-based LiDAR. The data gathered from surveys have been used to perform rockfall simulations and define potential mitigation measures. Finally, innovative visualization techniques based on the use of Virtual Reality will be introduced for an improved interpretation of geological and structural data and simulation results.

Anionic polyacrylamide as an additive to prevent soil proneness towards land degradation leading to slope instabilities

Giulia Frutaz, Massimiliano Bordoni, Claudia Meisina — Tue, 25 Jun 2024 00:00:00 +0000

Climate change and the intensification of extreme weather events constantly pose new threats to all human activities, damaging roads and communication networks, as well as economical activities and threatening human lives. Recently new materials are being considered as potentially useful tools in the prevention of land degradation leading to slope instabilities; among them polymers such as anionic polyacrylamide (PAM) are gaining more and more interest. PAM is known and employed as an additive in agriculture, in the prevention of irrigation-connected erosion, to maximize irrigation and fertilization efficiency and to enhance agricultural yield. Samples were reconstructed in laboratory using kaolin clay and silty sand, respectively, without mixing them to observe the effects of application of anionic polyacrylamide (PAM) on their physical, volumetric, mechanical, and hydrological properties. Fixed values were dry density (1.2 g/cm3 for kaolin clay and 1.4 g/cm³ for silty sand), initial water content (20% and 25% respectively) and polymer application rates (moving from the original 0%, 0.003%, 0.03%, 0.3%, 1% by weight for both “parent materials” to 0.01%, 0.03% and 0.05% for kaolin clay and 0.1%, 0.3% and 0.5% for silty sand, based on the results of previous analysis). Additional samples consisting of kaolin clay and quartz powder and polyacrylamide (with a concentration of 5% and 50%) were reconstituted specifically for ESEM analysis. The polymer, a granular anionic polyacrylamide provided by Micronizzazione Innovativa Srl, has been manually applied and mixed with the samples, reconstituted in pvc cylinders with a diameter of 9.5 cm and 5 cm high (although some were reconstituted in different cases for specific tests). Samples were then submitted to Atterberg limits with different curing times, hyprop and filter paper tests, WP4C, shear tests, and the record of volumetric characteristics. Results showed that the increase of PAM percentage in samples generally coincided with a widening of samples plasticity range, as well as with the increase of liquid limit and plasticity index; PAM influence was also a matter of time, being more relevant few days after the treatment and then slowly decreasing. Rise in PAM percentage coincided with an increase in samples porosity, and with a higher water retention, although it was impossible to identify a polymer characteristic structure with SEM analysis. These results can shed light on the potential application of polymers such as anionic polyacrylamide as a useful additive for the improvement of soil characteristics that impact on soil stability, in a frame of sustainable solutions for reduction of landslides susceptibility, hazard and risk.

Integrated analysis of triggering and runout susceptibility to landslide-induced debris flows in Alpine catchments

Tue, 25 Jun 2024 00:00:00 +0000

In the last decades the Valtellina valley (northern Italy) has suffered from several catastrophic rainfall-induced shallow landslide events inducing debris flows. The growing of urban settlements has driven population to colonize areas at risk, where prediction and prevention actions are nowadays a challenge for geoscientists. Debris flows are widespread in mountain areas because occurring along steep slopes covered by loose regolith or soil coverings. Under such conditions, heavy rainfall events might cause slope instabilities due to the increase in pore water pressure depending on hydraulic and geotechnical properties as well as thicknesses of soil covers. Despite the initial small volumes, debris flows hazard is significant due to the sediment entrainment and volume increase of the involved material, high velocity and runout distance. In such a framework, predicting timing and position of slope instabilities as well as paths, volumes, and velocity of potential debris flows is of great significance to assess areas at risk and to settle appropriate countermeasures. In this work, back analyses of debris flows occurred in representative sites of the Valtellina valley were carried out with the aim of understanding their features and providing a methodological basis for slope to valley scale susceptibility mapping. Numerical modeling of slope stability and runout was completed allowing the identification of the detachment, transport, and deposition zones of previously occurred landslides, including other potentially unstable ones. Results from this study emphasize issues in performing distributed numerical modeling depending on the availability of spatially distributed soil properties which hamper the quality of physicsbased models. In the framework of hazard mapping and risk strategy assessments, the approach presented can be used to evaluate the possible runout phase of new potential debris flows recognized by geomorphological evidence and numerical modeling. Furthermore, analyses aimed to the probabilistic assessment of landslide spatial distribution, related to a speciﬁc value of rainfall threshold, can be considered as potentially applicable to multi-scale landslide hazard mapping and extendable to other similar mountainous frameworks.

The knowledge of the Vajont Landslide through the photos of Edoardo Semenza: the English exhibition

Monica Ghirotti, Domenico Calcaterra, Francesco Maria Guadagno — Tue, 25 Jun 2024 00:00:00 +0000

The “Vajont disaster” of 9 October 1963, a paradigm of the catastrophe of human origin, is illustrated through the exceptional photos taken by Edoardo Semenza before and immediately after the event, presented in a new English exhibition. Edoardo Semenza was a geologist and one of the Italian leading landslide researchers. He put his distinctive mark on the understanding of the Alps, making original contributions to the geology, tectonics and geomorphology of the Dolomites. Semenza was the geologist who discovered that an ancient landslide mass was present on the southern side of the Vajont valley upstream from the reservoir under construction, before the first movements occurred on the slope. In the images shown in the thirteen roll-ups that make up the exhibition (Fig. 1), the intuitions, growing awareness, and sense of urgency of the man who first recognized the existence of the ancient landslide become evident. They reveal his “mente et malleo” (“with the mind and the hammer”) approach, which allowed him to develop a model of the slope and what today we call risk scenarios. His discovery was immediately taken into consideration by the designer and project managers of the dam, albeit only
as a hypothesis to be verified with follow-up research and investigations. Unfortunately, his work, which lasted until 1961, did not prevent the disaster from taking place. The hundreds of photos of the landslide and of the valley taken by Semenza between 1959 and 1963, allow us to access both his intimate and personal, and professional dimensions. A part of these materials, taken from the volume and CD “The photos of the Vajont landslide” and from Edoardo Semenza’s book on the landslide, is shown in the roll-up banners, and constitutes a contribution to the discussion. Texts, images and captions are selected and adapted from these two publications. Through this exhibition and a renewed attention to Semenza’s work we hope to raise awareness on the fundamental role that the knowledge of geology holds for the respect and protection of the environment. The first version of the exhibition “La storia del Vaiont: la conoscenza della frana attraverso le foto di Edoardo Semenza” was organized by AIGA and the National Council of Geologists (CNG) on the occasion of the fiftieth anniversary of the landslide (Genevois & Prestininzi, 2013). It was hosted by over 30 university campuses, several high schools, research centers, and museums. Launched in Naples during the National Conference of Young Researchers in Engineering Geology in February 2013, it continued its journey throughout Italy. By the end of 2014, it had been visited by several thousand students. Surrounding it, the departments or museums that hosted it organized significant events of a educational/scientific nature. It contributed to the spread of geological culture in general. It also received extensive coverage in national and local media and newspapers. In 2023, a renewed graphical version of the exhibition, in English, was realized by the Italian Association of Engineering and Environmental Geology (AIGA - Associazione Italiana di Geologia Applicata e Ambientale) and presented to the public on the occasion of the 6th World Landslide Forum in Florence for the sixtieth anniversary of the Vajont disaster. The landslide is still today the subject of debate and scientific reflection, due to the extraordinary amount of data available, as well as to the corpus of memories, stories, and testimonies that affected communities preserve and continue to build. Semenza repeatedly stressed the need to collect field data to understand slope failure conditions as a basis of correct landslide modelling. He strongly believed both in the role of geology and geomorphology as fundamental support to any engineering project and in the importance of a good communication between the various specialists working on large projects. In these aspects, just like in his research work, he was a
pioneer and a leader for the whole geological community.

Groundwater heat pumps diffusion in the Turin City urban area: modelling for the thermally affected zone analysis of an open-loop geothermal system

Martina Gizzi, Alessandro Berta, Federico Vagnon, Glenda Taddia — Tue, 25 Jun 2024 00:00:00 +0000

In urban areas with favourable geological and hydrogeological conditions, Groundwater Heat Pumps (GWHPs) offer an efficient solution for reducing emissions in heating and cooling systems. Turin City’s alluvial shallow aquifer serves as a valuable resource for harnessing low-enthalpy geothermal energy. However, a site assessment to evaluate the consequences of the technical solutions when promoting GWHPs is essential. Despite their proven potential in terms of energy efficiency, the environmental impact is a factor that can limit their development. This study reconstructs the impact of 44 open-loop geothermal systems in Turin’s area: an urbanscale numerical model was set up, and two simulation scenarios have been performed. The impacts simulated around the university buildings of the Politecnico di Torino are described. Findings from the average flow rate scenario demonstrated the absence of relevant hydraulic and thermal disturbances. The aquifer shows a positive response over three years, even in the maximum flow rate (Qmax) scenario with cooling/heating operating seasons for six months/year. However, due to changes in natural groundwater temperature connected to the Qmax scenario, downstream systems could experience adverse effects due to thermal interference. Precision in designing the construction of a new geothermal structure is crucial,particularly in areas with complex extraction systems.

Initial-level reports of landslides involving bridges and viaducts: the case study of Villa Ilii (Central Italy)

Tue, 25 Jun 2024 00:00:00 +0000

In the last decades, the concern for infrastructure damage and collapse due to natural hazards has globally increased. Highways, railways, bridges, and tunnels, worldwide, have faced consistent damage or destruction from landslides and floods, exacerbated by the ongoing climate change and population growth. In Italy, significant examples of these events are the recent failures of the Polcevera and Magra bridges, impacting people and the local economy. Especially, after the Polcevera bridge collapse, the Italian government has considered the need for specific practices of bridge/viaduct risk assessment. In response to this requirement, governmental agencies have developed specific projects oriented to the development of specific guidelines. This work is part of one of these projects, entrusted specifically to the ReLuis consortium, aimed at contributing to the application and optimization of an experimental protocol for bridge/viaduct classification in natural-hazard related risk assessment perspective. In this context, this work describes the results of an initial-level analysis of the interaction condition of a slowmoving landslide with the “Villa Ilii” Viaduct located along the A24 highway at Colledara, in the Teramo Province. The analysis aims to evaluate landslide characteristics, including landslide anatomy and kinematics, and their potential impact, contributing to define and identify viaduct classification in landslide risk perspective. The study area is characterized by the presence of the Laga Formation, mainly represented by sandstones and marls, overlaid by sandy Quaternary deposits. In fact the formation of the Laga (Ricci Lucchi, 1975) represents the filling of one of the many foreland basins currently exposed in a wide area between southern Marche and northern Abruzzo, developed at the forefront of the Apennines during its migration eastward and northeastward, as a result of the collision between the European lithospheric plate and the Adriatic plate, a likely protrusion of the African continent.), Methods including existing data collection, field surveys, numerical chartography analysis, geophysical surveys and PS InSAR technique were used to reconstruct the geological setting of the slope affected by the landslide, its anatomy and kinematics. Especially, multiple field surveys and numerical cartography analysis revealed landslide extent over a surface of 78,000 m², geophysical survey indicated a landslide thickness of around 15 m, comparable with the thickness of Quaternary deposits, and SAR-interferometric data, processed by SUBSIDENCE software, indicated persistent slow movement typically accelerating in spring. These data are crucial for understanding the landslide’s potential impact on the “Villa Ilii” viaduct’s structural conditions, already exhibiting local deformation and cracking, similar to surrounding settlements.

Terzaghi’s effective stress principle and hydrological deformation of karst massifs detected by GNSS and InSAR

Guido Leone, Michele Ginolfi, Libera Esposito, Francesco Fiorillo — Tue, 25 Jun 2024 00:00:00 +0000

Previous studies have shown that carbonate massifs of the Apennine chain (Italy) undergo deformation in response to groundwater level variations occurring in the saturated zone of karst aquifers. This study focuses on the Matese massif, hosting one of the main karst aquifers of the central-southern Apennine. Our analyses revealed a hydrological component in the time series of the horizontal and vertical ground displacements measured by GNSS (Global Navigation Satellite Systems) and InSAR (Interferometric Synthetic Aperture Radar). In particular, contraction and dilatation phases of the karst massif appear associated with the lowering and rising of the groundwater levels, respectively. Various authors have explained this phenomenon by the widening and closing of sub-vertical waterfilled fractures dissecting the rock mass due to varying hydraulic heads, neglecting the role of the effective stress state acting in the aquifer saturated zone. We present new equations explaining the observed deformational phenomenon in its generality, which are based on Terzaghi’s effective stress principle (Skempton’s generalization) and linear elasticity. The study shows that hydrological deformation of karst massifs is similar to the thermal expansion of solids. In the first case, the deformation is primarily due to pore water pressure variations occurring in the aquifer saturated zone, which are associated with water table oscillations, and is controlled by the elastic properties of the rock mass and the coefficient of earth pressure at rest, K0.

Sinkhole occurrence and evolution, and seawater intrusion in a low-coastal setting of Apulia

Isabella Serena Liso — Tue, 25 Jun 2024 00:00:00 +0000

In the last decades, the scientific community has paid an increasing attention on coastal karst areas, since these are highly urbanized and populated, and attract high number of tourists. This transition zone where anthropogenic, terrestrial, and marine processes simultaneously act, is intrinsically fragile, and its vulnerability to geological hazards is enhanced by the mixing between fresh and salt waters, causing a stronger dissolution on carbonate rocks. In this paper, a case study located along the coastal karst of Apulia, between the provinces of Bari and Brindisi, in one of the most touristic areas of the Region is described. In detail, this manuscript deals with description sinkholes evolution at the coastal zone and seawater intrusion in coastal aquifer. The case study highlights the influence of sinkholes in the modification of coastal geomorphology, potentially leading to natural hazards in terms for communities, urbanized land, and infrastructures. The geological setting presents the Cretaceous limestone bedrock overlain by more recent Cenozoic calcarenites and Quaternary marine terrace deposits. The topography is controlled by structural discontinuities, mainly oriented in SW-NE direction. This area is locally defined “Costa Merlata”, which means “Merlon coast”, as it resembles the merlons of a medieval castle. This is due to a strong control exerted by sinkholes in the genesis of bays and inlets. In fact, in this stretch of the Adriatic coastline, it is possible to observe important freshwater outflows, including the main spa of central Apulia (Torre Canne spa), and several evidence of sinkholes, including recent collapse at a few meters from the coastline. The morphologic evolution is characterized by different phases: individual openings of sinkholes, which evolve to small inlets showing the larger sinkhole inland, accompanied by minor openings toward the sea; the last phase is characterized by well-developed bays, deriving from coalescence of sinkholes, overall entering inland for some tens of meters, by means of progressive failures, also favored by sea-storms. In addition to the sinkhole hazards, the area is affected by inland seawater intrusion. In fact, the hydrogeological setting of the coastal stretch, extending for about 25 km, shows evidence of groundwater salinization, with salinity values ranging from 0,5 g/l to more than 5 g/l. The springs with high discharge rate are in the sand dunes zone (Fiume Grande, Fiume Piccolo, and Fiume Morello) and discharge hundreds of liters of freshwater per second, while several diffuse springs, often with unknown discharge, are submerged. In such complex zone, caves adopted as groundwater monitoring spots, especially near the sea, where fresh water and sea water meet. The latter is also carried out by monitoring of stygofauna, i.e. animal species living exclusively within groundwater. Stygofauna can be considered environmental indicator and natural tracer, since it is highly sensitive to environmental variation; therefore, studying groundwater ecosystems will allow to characterize the groundwater quality and the main freshwater pathways.

Hazard assessment of a rocky slope of Mount Pellegrino (Northern Sicily): a comparative study of direct and indirect approaches

Giampiero Mineo, Marco Rosone, Chiara Cappadonia — Tue, 25 Jun 2024 00:00:00 +0000

The assessment of landslide hazard related to slopes in fractured rock masses is generally correlated with the probability of occurrence of potential rockfall phenomena. The propensity to detachment of rock blocks can be defined through direct or indirect approaches. The first, widely used for decades, is regulated by the International Society for Rock Mechanics recommendations, and provides for the definition of a series of parameters for discontinuities that cross a line designated by the operator, according to the so-called “scanline” methodology. The most applied indirect approaches are based on the construction of a 3D model of the studied front through input data acquired by a digital camera, laser scanner or radar. These two different approaches were used to analyze the discontinuities orientation of a rocky slope on the west side of Mt. Pellegrino (northern Sicily). In this context, it is essential to anticipate rockfall, given the presence of densely urbanized areas at the foot of the rocky slope. The main discontinuity sets were obtained from traditional geo-structural analysis and 3D Point Cloud model of the slope; the latter were derived by applying the Structure from Motion technique on frames captured during the surveys. The kinematic analysis applied to the obtained data allowed us to define from a geomechanical perspective, the main modes of failure. Moreover, back analyses were carried out on the already collapsed blocks to reveal the most likely rockfall volume and reached distance.

Landslide impact on nature reserves: first results on the multisensor survey of unstable slopes in protected areas

Tue, 25 Jun 2024 00:00:00 +0000

This study is focused on the use of digital close-range remote surveying techniques for the identification and mapping of landslide phenomena along rock slopes in protected areas. This activity is part of a research project aimed at the digital analysis of slope models. The techniques compared herein are based on photographic and photogrammetric applications, carried out from both ground and aerial surveys, and on the use of infrared thermography in two test sites located within the Cinque Terre National Park (Liguria, Italy) and the “Timpa di Acireale” nature reserve (Sicily, Italy). The analysis of oblique aerial photographs allowed detecting key geomorphological indicators of past landslide movements and to carry out preliminary observations on unstable outcrops. The use of digital close-range sensors for the aerial photogrammetric survey allowed building a digital slope model to be analysed for the recognition and mapping of previous landslides. Moreover, key structural features, likely controlling the slope stability, were highlighted. Infrared thermography allowed detecting signs of landslides, providing the possibility of validating the photogrammetric data. In both protected areas, an almost zero level of environmental disturbance was guaranteed. Finally, both the potential and limitations of the techniques, used for the noninvasive morphological survey, are highlighted.

Seawater intrusion modeling under climate and anthropogenic changes in the Metaponto coastal aquifer (Basilicata, Southern Italy)

Rosalba Muzzillo, Filomena Canora, Francesco Sdao — Tue, 25 Jun 2024 00:00:00 +0000

The Metaponto coastal plain, located in the Basilicata region (southern Italy), is a relevant area for economic development due to the touristic and intensive agricultural sectors. In the 20th century, the land reclamation works, irrigation systems, and wells exploitation to support agriculture and industry strongly impacted the hydrogeological system, intensifying the potential seawater intrusion (SWI) that must be considered relevant in this coastal aquifer. The effective infiltration rate of the area is moderate due to the Mediterranean climate conditions, characterized by high temperatures and scarce precipitation concentrated mainly in winter. The present study aims to evaluate and model the SWI process in the most prone area of the Metaponto coastal plain. Groundwater flow and variabledensity transport, under steady-state and transient conditions, were simulated with MODFLOW and SEAWAT codes integrated into Visual MODFLOW Flex 7.0 software. The pumping rate effects and the impact of climate change on the aquifer recharge were considered in different scenario simulations. The results highlighted that the SWI is potentially not negligible in the future under exploitation and may impact the groundwater SWI level risk. The numerical modeling outcomes presented in this work can be used for the effective management of the Metaponto coastal plain groundwater resources.

Definition of runoff thresholds integrating satellite data and in-situ measurements: results from Voineşti Experimental Basin (Romania)

Tue, 25 Jun 2024 00:00:00 +0000

Understanding runoff-controlling mechanisms requires hydro-meteorological data derived from experimental plots or catchments. The present study focuses on the Voineşti Experimental Basin (VEB - Romania), which is in the Curvature Subcarpathia and is characterised by outcropping continental fluvial deposits. VEB has different experimental plots built to understand the relations between runoff and its genetic and predisposing factors. The study analysed the monitoring data in a plot of 600 m2 covered by grassland. An empirical model defined the runoff threshold by integrating ground data and satellite estimations. By identifying 45 runoff events in the 2016-2018 period, it was possible to define a runoff threshold considering the rainfall depth and the antecedent soil hydraulic conditions. Two indices were used based on the previous volumetric water content and the antecedent degree of saturation retrieved by the Copernicus Sentinel-1 mission. By adding the rainfall depth to the soil antecedent hydraulic conditions, a runoff threshold of about 65-67 mm was identified. These findings encourage using satellite moisture products to describe hydrogeological processes in scarcely instrumented areas.

Satellite radar interferometry for the analysis of potential instability in urban areas of high historical and cultural value

Tue, 25 Jun 2024 00:00:00 +0000

Satellite radar remote sensing techniques are non-invasive methodologies that can be effectively used for diagnostic purposes, measuring displacements, and monitoring cultural assets, architectural structures, and archaeological areas without injuring their integrity. The environmental condition and hydrogeological hazard in the Italian territory could make its invaluable Cultural Heritage at risk. Therefore, within the National Extraordinary Plan for Monitoring and Conservation of Cultural Heritage, an agreement has been established between the Ministry of Culture and the UNESCO Chair of the UNiversity of Florence on Prevention and Sustainable Management of Geo-hydrological Hazard to analyse ground motion rates on built-up areas by means of acquisition and PSI (Persistent Scatterers Interferometry) elaboration of high-resolution Cosmo-SkyMed synthetic aperture radar (SAR) satellite data (X-band). This technique can provide useful support on the conservation and protection of Cultural Heritage, as it endorses an innovative perspective on the condition and safety of historical sites, monuments, archaeological sites and artworks, thus contributing significantly to their preservation over time. Through SAR interferometric techniques, it is possible to identify millimetric displacements related to environmental threats, such as slow-moving landslides. This work proposes the classification of buildings of urban areas by using two indices based on PSI data coverage and deformation rates: the data coverage index in each building (Id) and the average velocity index of PSI data in each building and its surroundings (Ivmean), representing deformation rates in a locally scaled, easily understandable color-coded format. This method has already been tested in scientific literature on other SAR datasets for evaluating instability at the building scale. The approach aims to develop a fast and low-cost system to assess buildings that are potentially exposed to deformation and therefore more susceptible to damage in heavily urbanized areas with high historical-cultural value. In order to safeguard Cultural Heritage from natural disasters, the proposed methodology integrates a high degree of scientific and technological expertise and presents an updated and accurate screening of potential deformations due to hydrogeological hazards.

Multi-temporal evolution analysis of Maronti Cliff (Ischia Island, Italy) derived from multi-perspective photographic datasets

Tue, 25 Jun 2024 00:00:00 +0000

Coastal cliff erosion is a significant hazard for the safety of people, buildings, utilities and infrastructure, given the sudden and episodic nature of the retreat process in time and space. Thus, understanding past retreat trends and a regular diagnosis of the cliff face condition is fundamental for risk management. In this study we show preliminary results of a project aimed at the definition of the coastal erosion (in terms of temporal and spatial scales) of a small portion of cliff located along the Maronti beach in Ischia, Italy. Drone-based and terrestrial acquisition approaches offered the opportunity to exploit photogrammetric techniques to estimate the spatial and temporal rate of change of the investigated portion of cliff. In this study, cliff face topographical evolution is evaluated out by comparing the results obtained from three photographic datasets (variable approach either boat and UAV-based) obtained in 2011, 2021 and 2023. Spatial distribution of two main instability events dated back to 2020 and 2022 were well represented in the maps of change generated with the M3C2 algorithm. The comparison of point clouds for the period 2011-2021 and 2021-2023 produced max retreat rate of the cliff face of approximately 12 and 25 m, respectively. Results highlighted the need for robust co-registration methods to accurately estimate erosion rates. Critical issues are discussed to highlight potentials and limitations encountered with the abovementioned multi-temporal cliff evolution assessment techniques.

Pore network model to predict flow processes in unsaturated calcarenites

Tue, 25 Jun 2024 00:00:00 +0000

The knowledge of infiltration mechanisms in vadose zone is the key to forecast the components of the hydrologic cycle such as run-off generation and aquifer recharge. Besides, slope stability, settlements and bearing capacity of foundations, and rock weathering are issues in which infiltration processes play an important role. In Apulia and Basilicata (Southern Italy) representative calcarenites outcrops are exposed along both the coastline and internal areas. These calcarenites belong to the Calcarenite di Gravina Fm. (Middle Pliocene-Lower Pleistocene) and are mainly constituted by fine- medium- and coarse-grained packstones and grainstones. The whole geological formation represents an important hydrogeologic unit which controls groundwater recharge and transport of contaminants within a complex, multilayered system comprising a wide and deep aquifer hosted into the Mesozoic basement. A smart analytical and numerical tool based on the pore bundle model conceptualization and the Richards’ equation was developed to predict infiltration and retention mechanism of calcarenites. This work investigated the impact of bimodal poresize distribution on the unsaturated flow from dry to wet conditions obtained through conventional and unconventional laboratory tests and petrophysical characterization, also completed with mercury intrusion porosimetry and image analysis. Laboratory experiments were carried out on medium-grained grainstones sampled at Canosa di Puglia (Tufarelle locality), by means of infiltration tests conducted starting from a different degree of saturation and varying the inlet flow rate. The experimental data were compared with the pore network model prediction. For the rock samples used, the study disclosed that macroporosity mainly affects the propagation of the wetting front and infiltration rate. Thus, the wetting front develops principally during the infiltration of water through the interconnected macropores following the pathways having minimum flow resistance with a gravity driven flow velocity higher than the diffusive flow though micropores.

A new perspective for regional landslide susceptibility assessment

Giacomo Titti, Matteo Antelmi, Francesco Fusco, Laura Longoni, Lisa Borgatti — Tue, 25 Jun 2024 00:00:00 +0000

Landslides pose a severe geohazard in many countries. The availability of inventories depicting the spatial and temporal distribution of landslides is crucial for assessing landslide susceptibility and risk in territorial planning or investigating landscape evolution. In the case of the Italian territory, several landslide hazard and risk maps were produced ranging from regional to national scale. This was made possible leveraging public domain data of the Italian Landslide Inventory (IFFI project; Trigila et alii, 2010), or other geodatabases spanning from local to regional scale. However, the practical utility of this inventory is often limited in many applications due to its spatial inhomogeneity or the use of different mapping methods and classification criteria. Despite the impressive advancements in techniques for assessing natural hazard susceptibility at a national scale over the past years, including statistical models, AI based models (i.e. Neural Networks) and others, the results are still limited by the quality of the data used. Specifically, the effectiveness of these models is closely tied to the quality of the landslide inventory utilized. Currently, recent regional landslide inventories could potentially enhance precision and accuracy compared to the national dataset, primarily owing to their finer resolution compared to the IFFI dataset. In this work, we present a new approach to assess landslide susceptibility at local scale, relying on regional landslide inventories. Using a data-driven technique, we propose to train a single model on a landslide inventory consisting of a composition of regional inventories selected to be representative of the national scenario. The weighted model is now capable of predicting landslide susceptibility in any study area across Italy. The entire analysis has been done using the SRT tool for Google Earth Engine and the SZ-plugin for QGIS. All the data used and processed are freely available and downloadable. The proposed approach has been tested in the framework of the PNRR RETURN project. The evaluation was conducted in two specific areas: the first one encompasses a section of the railway connecting Napoli to Bari (southern Italy), while the second focuses on areas impacted by the Marche region 2022 landslide event (central Italy).

Cascading landslides at Morino-Rendinara, L’Aquila, Central Italy: numerical modelling of slope-scale prospective debris flow propagation

Tue, 25 Jun 2024 00:00:00 +0000

Cascading landslides are sequences of multiple landslides that commonly involves significant volumes of material and exhibit variable velocity up to several m/s. The impact of these processes is generally significant so that they can claim victims and be responsible of significant losses. Considering the complexity of the process, their mitigation involves the understanding of causeeffect relations between the initial triggering event and subsequent cascading processes as well as the development of methodological framework for their analysis. On this basis, this work aims to analyse the characteristics of the cascading landslide event of Morino-Rendinara, in the L’Aquila province, applying a procedure that, comprising multiple methods, is capable of providing data depicting mechanism and kinematics of the system, anatomy of landslides and prospective susceptibility scenario.

Groundwater flow numerical analysis of the Sibillini Hydrostructure (Central Italy): system characterization and evaluation of hydrogeological changes after the Mw 6.5 Norcia Earthquake

Tue, 25 Jun 2024 00:00:00 +0000

The October 30th Norcia earthquake originated from the rupture of different segments of the Vettore-Bove normal fault system. The co-seismic rupture propagated up to the surface, causing important faulting and affecting the hydrodynamics of the Basal Aquifer of the Sibillini Mts. carbonate hydrostructure. Several long-lasting hydrogeological changes occurred at springs over the impacted area. Such changes indicate the disruption of the hydraulic sealing effect of the Vettore fault because of the co-seismic dislocation and the consequent groundwater flow increase through the broken fault. This work aims at characterizing the complex regional hydrogeologic system of the Sibillini Mts. and evaluating the important earthquake-induced hydrogeological changes by means of numerical modelling. A robust conceptual model has been defined according to tectonic and hydrogeological data and based on a 3D reconstruction of the Basal Aquifer. The regional-scale extent of the model allowed us the adoption of a simplified approach treating the carbonate aquifer as a continuous and homogeneous equivalent porous medium, while faults were considered as hydraulic barriers with lower permeability. Simulation results, aligned with the observed variations, highlight the crucial role of faults in influencing the hydrodynamics of carbonate hydrostructures.

Foreword

Domenico Calcaterra, Gabriele Scarascia Mugnozza, Rita Tufano — Tue, 25 Jun 2024 00:00:00 +0000