HAL-BRGM, les publications scientifiques en libre accès du BRGM
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A coupling approach for long-term 3D morphological evolution of sandy coasts under sea-level rise
No full textInternational audienceThis study presents a modular modeling framework for simulating medium- to long-term (decadal to centennial) coastal evolution, focusing on shoreface translation under the combined effects of sea-level rise (SLR) and waves. On these timescales, short-term storm-driven processes are treated as noise superimposed on longer-term trends. We couple the one-dimensional ShoreTrans model, which simulates SLR-driven profile adjustment, with the two-dimensional reduced-complexity model LX-Shore, which captures longshore sediment transport gradients. This coupling enables efficient simulation of three-dimensional morphological change across diverse sandy coastal settings, including environments with dunes, barriers, and hard structures. The framework is first applied to synthetic test cases to explore sensitivity to coupling strategies, then tested on a 5-km beach-dune system in southwest France fronted by a 1.2-km seawall. Results show reasonable agreement with observed shoreline evolution and demonstrate the value of the coupled approach in capturing morphodynamic feedbacks and trajectory shifts not reproduced when shoreline and shoreface processes are modeled independentl
Special issue "Effects of surface geology on seismic motion (ESG): general state-of-research"
No full textInternational audienceTo understand and predict the behaviors of strong ground motions incurred during devastating earth quakes, studies focused on the “efects of surface geology (ESG) on seismic motions” (following tradition, herein contracted as: “ESG”) have progressed steadily in the last three decades. Tese ESG studies typically involve in situ measurements of the wavefeld and commonly apply both analytical and computational approaches. Concur rently, improvements in ESG-related research can be readily attributed to the proliferation of openly accessible strong motion data, as well as advances in computational power. Nevertheless, there remain signifcant short falls in our understanding of the epistemic and aleatory uncertainties associated with the ESG as demonstrated by phenomena from recent deadly earthquake-related site efects. Tus, investigations toward addressing these defciencies should be underscored in future earthquake related disaster mitigation efort
Damage assessment in the case of post-mining-induced seismicity: How to use and adapt macroseismic intensity scales?
No full textInternational audienceFollowing coal mine closures, the impact of flooding on underground mining excavations and on the geomechanical stability of the rock mass has the potential to trigger superficial earthquakes. The generated vibrations may induce damages to the surface infrastructures. Therefore, they represent a significant source of concern for the population. Nowadays, seismic risk assessment procedures in Europe usually build upon the EMS-98, which has been developed for natural tectonic earthquakes. This study aims to investigate the applicability of EMS-98 to seismic events induced by post-mining context while comparing it to a new intensity scale MSIIS-22 adapted to very low intensities from mining-induced earthquakes. To this end, three damage assessment methods are proposed: application of EMS-98 coupled with a semi-empirical vulnerability approach, direct application of MSIIS-22 and its intensity damage correspondence, and adaptation of the semi-empirical vulnerability approach to MSIIS-22 using observed data. This framework is applied to two testing sites that have experienced mining and postmining-induced seismic events. The results show that damage estimates from the three methods are similar despite differences in the definition of the intensity degrees and damage states. Further data from post-mining-induced seismic events would be needed in order to confirm these preliminary finding
AfricaMaVal -Mineral Potential Mapping study of European Critical Raw Materials (ECRM) of Africa
No full textInternational audienceThe AfricaMaVal project, a 3.5-year initiative coordinated by the French Geological Survey (BRGM), aims to establish sustainable partnerships between the European Union (EU) and African countries in the critical raw materials sector. With 18 partners across 11 countries, the project focuses on responsible mineral sourcing for European industries while fostering sustainable local development in Africa. A key objective of the project’s Work Package 1 (WP1), "Supply Potential," led by the Portuguese Geological Survey (LNEG), is to assess and map the supply potential of European Critical Raw Materials (ECRM) across Africa. This involves creating a harmonized and INSPIRE-compliant database to identify and evaluate the availability of these minerals and metals, which are crucial for Europe's energy and digital transitions. Machine learning (ML) algorithms for mineral resources assessment were developed at BRGM over the last 20 years and have been used on a larger scale since 2022. As part of the AfricaMaVal WP1, mineral prospectivity maps were produced for selected ECRM in ten partner countries. The database included the in-house BRGM data sets, including geological and structural maps of Africa at a scale of 1:10 million and more than 55,000 mineral occurrences across the continent. However, the resolution, quality and density of data varies greatly from country to country and sometimes almost no geoscientific information is available. Initial predictivity tests were carried out using the 1/10M geological map produced by BRGM and co published by CCGM (Thiéblemont, 2016). This map has the advantage of being coherent and uniform, but the resolution is insufficient to highlight well-defined potential zones that are relevant on a continental scale and does not facilitate the analysis of correlations between co-genetic mining substances and the geological events that generated them. To address this, further modelling was carried out using BRGM’s higher-resolution 1:2M geological map of Africa. After classifying the geology of the continent into a) major geological domains (orogenic belts, basins) and b) geological events from the Archean to the Cenozoic, the ML algorithms were used to identify areas that have potential for a specific commodity but are underexplored. This was done for most ECRMs listed in 2020. The new approach has the advantage that missing information in one country can be provided by information from neighbouring countries with similar geologic settings. The method also calculates factors that are favourable or unfavourable for finding a commodity in an area of interest or geological unit. The project’s final output includes multi-thematic maps that integrate mineral potential with infrastructure (power, roads, and seaports), protected areas, and small-scale mining activities. These maps serve as a first-order guide to mineral exploration and can be used to balance economic potential with environmental and social considerations
Inconsistencies in handling of multifunctionality in the environmental footprint of electric vehicle batteries: a cross-industry analysis
No full textInternational audiencePurpose: With the increasing importance of sustainable development, reflected in various policies, life cycle assessment (LCA) guidelines for different industries and materials have emerged in recent years, mainly linked to batteries and their raw materials. This paper analyses the inconsistency between different industries’ LCA guidelines, their practical implications and the potential way forward. Methods: In this publication, we analyse LCA guidelines for four key battery raw materials, namely lithium, nickel, cobalt and copper. We linked the materials to their relevant applications and industries, focusing on the multifunctionality handling in the different industries. The analysis considers two types of multifunctionality handling: co-production and recycling end-of-life treatment. We determine the consistency within and between applications and industries, as well as along supply chains from the material to the product, and analyse the implications of inconsistencies quantitatively and qualitatively. Based on the analysis results, we discuss key consistency checks needed in the future and potential pathways towards more consistency based on an influence–interest analysis of the involved industries regarding potential standardisation processes. Results and discussion: The analysis shows inconsistencies in the multifunctionality handling within and between applications and industries, as well as along supply chains. The discrepancies can lead to a variation of the climate change impacts per kilogram of material of up to a factor of five. Potential developments towards more consistency could be driven bottom-up by the metal associations or top-down by the different industries or as a combination of both. Attention is needed regarding the upcoming mandatory LCA guideline for batteries in the EU market. For overall consistency, international industries would need to align with this guideline. Until consistency is reached, transparency on methodological aspects, potential inconsistencies and their implications is crucial. Conclusions: Multifunctionality handling is only one relevant consensus aspect for which this comparison must be made between various applications and industries. Other aspects are, for example, electricity modelling and impact assessment methods. An extension of this work is needed to cover all potential inconsistencies and guide future standardisation. This could be supported by further analysis of possible pathways and the development of guidance for a consensus process towards standardisation
Comprehensive Physicochemical and Biological Analysis of Hydroxyapatite/Dextran Powders before and after Immersion in Kokubo Solution
No full textInternational audienceUnderstanding the behavior of biomaterials under physiological conditions is essential for the development of new materials for implants and bone regeneration. This study addresses the critical need to evaluate how exposure to simulated body fluid (SBF) affects hydroxyapatite (HAp) and dextran-coated hydroxyapatite (HApDx) nanoparticles, which are widely considered for biomedical applications due to their bioactivity and biocompatibility. Structural, morphological, and surface property changes induced by SBF immersion were systematically investigated for the first time using advanced characterization techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), FT-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and fractal and Minkowski functional analyses. The results revealed that SBF immersion significantly influenced both HAp and HApDx, leading to reduced crystallite sizes, surface smoothening, and enhanced structural homogeneity. FTIR and FT-Raman spectra indicated subtle structural modifications, while SEM and AFM analyses confirmed the formation of a biomimetic apatite layer and a decrease in surface roughness. These changes are indicative of improved bioactivity, suggesting enhanced potential for osteoconductivity and cellular interaction. Biological evaluations using MG63 osteoblast-like cells demonstrated favorable cell viability and adhesion across 24, 48, and 72 h, particularly for the samples immersed in SBF. AFM further confirmed that surface modifications supported the cell attachment and proliferation. Overall, our findings underscore the importance of SBF exposure in enhancing the physicochemical and biological performance of HAp-based materials, reinforcing their promise for biomedical applications
Practical Data Assimilation for the Subsurface
No full textThis habilitation thesis explores the scientific challenges of characterising and modelling the subsurface, with applications in oil and gas, CO₂ storage, geothermal energy, and water resource management. A central focus is on model updating through data assimilation, enhancing predictive capabilities while quantifying uncertainty for operational decision-making. The work adopts a multiphysics, multiscale, and multisource approach, addressing the complexity of subsurface processes and how to integrate them in a sufficiently informative manner. The inverse problem, optimisation strategies, and advanced methods are examined as key tools for integrating data into predictive models and enabling ‘what-if’ scenario analysis. The study also explores digital twins as a promising avenue for enhancing the entire integration chain and supporting real-time decision-making. A computational strategy is proposed to balance model fidelity, data availability, and computational cost. Finally, the manuscript provides a long-term research perspective, highlighting digitalisation, fitness landscape approaches, and the future of computational geosciences
Oracle-Orgeval, Long-term Research observatory of the critical zone
No full textInternational audienceThe Orgeval Long-term Research Observatory, part of the French critical zone network (OZCAR RI), is a 104 km² agricultural catchment, located 70 km east of Paris, in France. The Orgeval catchment is representative of intensive agriculture (80 % of its total area), the main land use in the Seine river basin. For more than 50 years, both quantity and quality of water are monitored throughout the catchment, from sub-hourly to yearly time scales. This rich dataset allows improving the understanding of critical zone structure and reactivity, in a holistic and interdisciplinary approach. Specific basic and applied research topics relate to extreme hydrological events, agricultural tile drainage, land use planning, and more generally the evolution of agricultural activities facing climate change and urban growth. The Orgeval research observatory is a unique testbed to investigate the functioning and evolution of the Critical Zone. Multidisciplinary approaches are implemented thanks to collaborations between research institutes and universities, combining knowledge and methods from different disciplines, such as hydrology, ecology, biogeochemistry, geophysics and socioeconomics. Created in 1962, the observatory was initially devoted to study floods and weathering research questions. Since then, is evolved towards other societal and environmental topics. Initiated in 1975, lots of monitoring and research was dedicated to diffuse agricultural pollution, especially nitrates, which contributed to a better understanding of the interactions between agricultural activities and surface and groundwater quality. Since the 2000’s, research questions opened to pesticides and biology and biodiversity. The Orgeval observatory is also highly adapted to develop technological innovations, such as in situ biochemical monitoring. A multi-scale observation strategy is implemented in both space and time, ranging from local (with more than 80 monitoring sites) to regional scale, and from time-lapse campaigns to high-frequency measurements (from 1 Hz for geophysics to 1 h or 1 week for chemistry), most often with a long-term approach. The main measurements include: Water level and water discharge : at the outlet of each sub-catchment. groundwater level : in piezometers in the riverbanks and in the aquifers. Precipitation : in addition to Météo-France stations. Main weather variables : air temperature, humidity, and radiation. Soil moisture : from the soil surface to a depth of 1.5 meters. Water quality : dissolved organic and inorganic carbon, dissolved gases (O 2 , CO 2 , Rn), major and trace ions, nutrients, but also water, carbon or strontium stable isotopes. This includes the RiverLab prototype, installed in June 2015 at the outlet of Avenelles sub-catchment for high-frequency measurement (every 30 minutes) of the river's chemical composition. Organic and inorganic contaminants : pesticides but also metals and microplastics in surface and groundwater. Ecotoxicological and ecological indices : ecological assessment. Surface and groundwater temperature : using heat as a tracer of surface-groundwater exchanges. Hydrogeophysics : ERT, GPR, seismic, especially in the riparian areas. Borehole core samples and logging : lithofacies description and characterization. Water level and water discharge : at the outlet of each sub-catchment. groundwater level : in piezometers in the riverbanks and in the aquifers. Precipitation : in addition to Météo-France stations. Main weather variables : air temperature, humidity, and radiation. Soil moisture : from the soil surface to a depth of 1.5 meters. Water quality : dissolved organic and inorganic carbon, dissolved gases (O 2 , CO 2 , Rn), major and trace ions, nutrients, but also water, carbon or strontium stable isotopes. This includes the RiverLab prototype, installed in June 2015 at the outlet of Avenelles sub-catchment for high-frequency measurement (every 30 minutes) of the river's chemical composition. Organic and inorganic contaminants : pesticides but also metals and microplastics in surface and groundwater. Ecotoxicological and ecological indices : ecological assessment. Surface and groundwater temperature : using heat as a tracer of surface-groundwater exchanges. Hydrogeophysics : ERT, GPR, seismic, especially in the riparian areas. Borehole core samples and logging : lithofacies description and characterization. All these data support the development and use of numerical models, for scientific questions but also for environmental impact assessment and territorial management. This catchment is used to develop and/or validate numerical methodologies at the headwater catchment scale, in parallel to larger scale modeling (typically for the Seine river basin
Colloid-induced clogging in porous media: 4D X-ray microtomography experiments
No full textInternational audienceColloids in geological porous media such as rocks and soils are relevant for a broad range of environmental applications, such as groundwater remediation. The transport of colloids, ranging from nanometers to micrometers in size, is shaped by pore geometry, surface interactions, flow conditions, and particle properties [1]. In the literature, colloids are widely reported to influence the mobility of contaminants in porous media at the column scale [2], however, the multi-scale mechanisms driving colloid-induced mobilization, from microscopic interfaces to pore networks and field-scale processes, are poorly understood. This study addresses this gap using time-resolved 3D X-ray micro-tomography to investigate colloid transport, pore clogging, and flow modification under transient conditions. By attaching to fluid interfaces, colloids can reduce capillary forces and aid non-aqueous phase liquids (NAPL) removal, while their deposition can clog pores and alter flow patterns [3]. Here we want to focus on modification in hydrodynamic forces due to pore clogging, which has already been evidenced by microfluidic experiments (as illustrated in figure 1b) [4]. Most of the previous studies at the continuum scale have focused on classical column experiments for colloid transport, missing the complex dynamics at the microscopic level. The existing pore scale studies either lack the third dimension (microfluidic experiments[5]), or in-situ imaging at sufficient spatio-temporal resolution to resolve the flow and transport [2]. To fill these knowledge gaps, this study aims to utilize X-ray microtomography that enables high-resolution, non-destructive imaging at the pore scale to investigate the mechanisms behind colloid-induced pore clogging, which modifies flow and mobilizes trapped NAPL in porous media [6]. Cylindrical samples of porous sintered glass (4 mm diameter, 40 mm length) with average pore throats in the range of 30–70 µm, are mounted in a flow cell (Figure 1a). To achieve our objectives, we conduct single-phase and multiphase flow experiments. We use three types of X-rays attenuating particles of varying sizes and surface properties to represent environmentally relevant colloids. This study is expected to provide insights into the role of colloids in pore clogging, and NAPL mobility