The Scientific 16th AGAP Days
About the AGAP Scientific Days 2026
AGAP Qualité organizes conferences called the AGAP Scientific Days. The 16th AGAP Scientific Days, held from March 24 to 26, 2026, at the University of Toulouse, bring together stakeholders from both the professional and research communities in applied geophysics.
To open the AGAP Scientific Days, Luc Sandjivy presents a lecture entitled:
Geophysics and Artificial Intelligence – What Revolutions?
If the ongoing digital transformation of our globalized societies is undeniably a revolution comparable to the Industrial Revolution of the 18th century in Europe, artificial intelligence (AI) is to this transformation what the steam engine once was to the Industrial Revolution. It is therefore entirely legitimate to analyze how this revolution is transforming our work as geophysicists, and to reflect on the relationship between AI and geophysics. Luc Sandjivy offers his answer to this question and provides a rich and captivating analysis.
Geophysical methods provide subsurface models that become increasingly accurate when they result from a combination of techniques along with an evaluation of the associated uncertainties. To assess the performance of geophysical methods—particularly imaging techniques—researchers often rely on synthetic cases or full-scale physical models that enable acquisitions comparable to those carried out during field surveys.
Paul Cupillard presents the PEGGHy model in a lecture entitled:
PEGGHy: A Controlled Geological Environment for Testing Geophysical Imaging Instruments and Methods
The Geophysical, Geotechnical and Hydrogeological Experimentation Platform (PEGGHy) includes artificial geological structures and anthropogenic heterogeneities whose geometry (shape and position) is fully controlled. The platform’s layers are composed of aggregates selected for their lithological properties, allowing the creation of significant geophysical contrasts. Additionally, PEGGHy contains localized anthropogenic heterogeneities capable of generating wave diffraction (seismic or electromagnetic) and small-scale anomalies. Thanks to photogrammetric data acquired by drone, the platform is accompanied by a 3D digital twin with centimetric accuracy. This digital tool makes it possible to quantitatively compare models obtained from geophysical data processing with the actual subsurface geometry, offering a unique opportunity not only to test but also to teach geophysical instruments and imaging methods.
The scientific days include conference sessions as well as equipment demonstrations by manufacturers and service providers.
The scientific days include four presentation sessions.
Session 1: On Electrical Measurements
Electrical imaging, commonly used to provide the subsurface resistivity distribution, is often combined with other geophysical methods in Multiphysics approaches.
In this session, the speakers show that:
- Joint inversion algorithms developed to simultaneously process refraction tomography and resistivity data help reduce equivalence issues related to solving the inverse problem and improve the quality of the final image.
- Capacitive Coupled Resistivity (CCR) tomography—a fast, non-invasive method particularly effective in urban environments and reliable for subsurface imaging—can distinguish resistivity contrasts associated with variations in facies type, backfill materials, as well as localized heterogeneities characteristic of structural pathologies.
- Advances in acquisition systems independent of induced polarization have enabled geophysicists to image deep geological targets, describe electrical conductivity processes, and access numerous properties relevant to geothermal exploration, such as alteration, water content, or mineral formation temperature. The use of petrophysical proxies allows quantitative analysis of geo-electrical data, including water content, permeability, and Darcy velocity.
Session 2: Geophysical Measurements Using Optical Fiber
To introduce the session, Florian Duret gives a lecture entitled:
Distributed Acoustic Sensing (DAS) Measurements in Geophysics: Influence of DAS Parameters on Seismic Measurements
In this session, the speakers present examples of the use of fiber optics and DAS systems for seismic acquisitions.
A first example shows the results obtained from a PSV-type acquisition on cemented fiber installed behind casing, carried out for reservoir monitoring studies during CO₂ injection.
ANDRA has deployed a network of fibers in horizontal boreholes drilled from an underground gallery of the Underground Research Laboratory located in Bure. Examples illustrate how fiber-based measurements are used to characterize the damaged zones created during the excavation of the gallery as well as the horizontal boreholes.
A final example describes experiments conducted in the ANDRA laboratory to transmit, for the first time, data from a depth of 490 m to the surface using seismic waves. This study is part of the development of wireless communication methods for the underground Internet of Things.
Session 3: Ambient Seismic Noise
To introduce the session, Ludovic Bodet presents a lecture entitled:
RAILWAVES 1.0 Toolbox: Toward Intelligent Integration of Geotechnical and Hydrogeological Data for the Diagnosis and Monitoring of Railway Platforms Using Surface Waves
In this session, the speakers show how ambient seismic noise measurements can be effectively used to estimate the shear-wave velocity distribution of geological layers in both 2D and 3D acquisitions.
The presented papers describe field implementations, including surveys conducted in complex environments for geothermal studies, as well as the inversion processes of surface-wave dispersion curves reconstructed through interferometry. It is notably shown that the simultaneous recording of ambient seismic noise on three-component sensor arrays arranged in a circle made it possible to jointly reconstruct and invert the dispersion curves of Rayleigh and Love waves, and to obtain the shear velocity distribution down to 150 meters depth.
It is also shown that passive seismic methods provide a non-invasive alternative for detecting and monitoring flow variations, particularly floods, in complex karst systems.
Session 4: Quantum Gravimetry
Gravity measurements contribute to subsurface imaging by providing direct information on underground mass variations. Quantum gravimeters use clouds of cold atoms as test masses and exploit their quantum properties to perform absolute gravity measurements. An absolute quantum gravimeter (AQG) has been available for several years. The new Differential Quantum Gravimeter (DQG) represents a major advance over conventional gravimeters by simultaneously measuring gravity (g) and its vertical gradient.
In this session, the first results of two European projects supporting the development and adoption of quantum technology in gravimetry—EQUIP-G (2025–2029) and FIQUgS (2022–2026)—are presented.
The speakers describe the principle and operation of the quantum gravimeter and present the EQUIP-G project and its consortium, whose goal is to deploy a network of quantum gravimeters across Europe and to establish an associated long-term community structure. As part of the FIQUgS project, the speakers present the project itself, the first field deployment of the DQG for cavity detection, the results of this survey, and the inversion strategy used to image the subsurface. The planned surveys at the end of the project are outlined, targeting archaeological applications, cavity detection, and geological structural characterization.
Jean-Luc Mari
AGAP Qualité, in association with EDP Sciences, publishes pragmatic books in the PROfile collection, called Cahiers de l’AGAP, which aim to transmit professional knowledge in the geoscience disciplines, primarily geophysics.
In 2025, the AGAP notebook Geophysics in Geothermal Exploration – A Review [1] was published.
The 16th AGAP Scientific Conference provides an opportunity to present the notebook titled:
A New Concept of Karst Development Based on Hydrogeology and Geophysics [2],
co-edited by Thierry Gaillard and Jean-Luc Mari.
1. Jean-Luc Mari and Geoffroy Paixach, 2025, Geophysics in geothermal exploration: a review, Collection Profile, ISBN(ebook): 978-2-7598-3752-6, DOI: 10.1051/978-2-7598-3752-6, https://doi.org/10.1051/978-2-7598-3752-6
2. Thierry Gaillard and Jean-Luc Mari, 2026, A new concept of karst development based on hydrogeology and geophysics, Collection PROfile, ISBN(ebook): 978-2-7598-3934-6, https://doi.org/10.1051/978-2-7598-3934-6
Committees
Organizing committee
J. Mention, M. Llubes, M. Hayet, P. Brunel, J.L. Mari
Selection committee
J.L. Mari, M. Hayet, C. Camerlynck, P. Frappin, P. Brunel, ...