As part of the SEIS-ADELICE project (2020–2025), hundreds of seismological instruments were deployed on and around the Astrolabe Glacier in Terre Adélie, East Antarctica. The aim was to monitor the cryoseismic activity of an Antarctic outlet glacier as it reaches the ocean, image its internal structure and thickness, and investigate its interactions with the underlying ocean and local bedrock. This paper describes the sequential deployment of broadband, mid-band, and short-period instruments on land and at sea, the noise levels obtained in various environments and the quality of the seismological data in different frequency bands. It also presents a few non-exhaustive examples of data to demonstrate their quality and potential for analysing various cryoseismic sources at different times, frequencies, and geographic scales.

Abstract. Ice-core drilling generates repeated mechanical disturbances within the ice column, raising the possibility that operational drilling signals could be used as opportunistic seismic sources. We test whether impulsive ice-core break-off events during the 2022 EastGRIP (Greenland) field season can be detected on surface-based, near-offset three-component geophones and used to estimate apparent P-wave velocity. A catalogue of 67 candidate core-break times was identified from drill-log load peaks, of which 37 had sufficient simultaneous near-offset seismic station coverage for assessment. Only three of these assessable events produced plausible impulsive arrivals. Automatic STA/LTA triggering was useful for identifying candidate windows, but did not reliably pick first arrivals. Where clear arrivals were identifiable above the background noise, manually picked arrivals gave apparent P-wave velocities consistent with firn/ice propagation, and showed a small across-flow faster-than-along-flow tendency, though this difference remains below the level of uncertainty required for robust anisotropy interpretation. These results show that ice-core break-off may provide a useful opportunistic seismic source, but only if future deployments include direct source-time measurement, quiet acquisition conditions, and receiver geometries designed for this purpose.

Icequake seismicity on coastal glaciers is thought to be controlled by ocean tidal forcing, but short deployments make this difficult to verify: in diurnal tidal environments, wind, temperature, and atmospheric pressure all vary on approximately 24-hour cycles near-indistinguishable in period from the K1 tidal constituent (23.93 hours). This near-collinearity means that naïve tidal analysis on a short record risks measuring the diurnal environmental cycle rather than a physical tidal response, an aliasing problem that has not, to our knowledge, been formally characterised or addressed in the seismological literature. Without a framework to separate the two, short-record analyses cannot determine whether an observed correlation between tidal height and seismicity rate is physical or spurious. A previous deployment on Astrolabe Glacier (Le Bris et al., 2025) identified a tidal phase signal but, suspecting that wind interfered with seismic detection, restricted their analysis to low-wind periods rather than systematically characterising the environmental confounders or quantifying how much of the observed signal could be attributed to aliasing rather than tidal forcing.The January 2024 SeisAdelice experiment on Astrolabe Glacier, Adélie Land, East Antarctica served as the development and testing site for a deconfounding framework targeting this problem. The network comprised 37 three-component seismic nodes concentrated within a 2 × 0.6 km strip across the glacier's grounding line (~150 m spacing), supplemented by two surface fiber arrays totalling 4 km (linear and z-configuration, 500 Hz, 2.4 m channel spacing). Analysis of the resulting icequake catalog confirms the severity of the aliasing: wind speed, air temperature, and geometric solar elevation together explain the dominant fraction of hourly seismicity variance and are strongly collinear with K1 on the 20-day record, so naïve correlation with tidal height gives a spurious result. We expect to have validated the framework against additional datasets by the time of presentation.The framework combines three complementary approaches: an environmental Poisson GLM that quantifies the relative contributions of wind, temperature, solar forcing, and tide to icequake rate; tidal phase analysis stratified by tidal regime to isolate the semi-diurnal M2 component; and per-station phase gradient analysis, which is immune to uniform detectability bias and provides spatially coherent corroboration. Preliminary results from Astrolabe confirm that the framework recovers a genuine tidal signal — seismicity preferentially elevated on the falling and low tide — that naïve correlation either mischaracterises or obscures entirely.The framework makes rigorous tidal analysis tractable for short deployments in tidally forced coastal environments without requiring the multi-year records that would be needed to separate K1 from the solar day spectrally, a practical constraint that makes remote polar fieldwork particularly vulnerable to this aliasing problem.

Terrestrial ice bodies are important regulators of climate and sea level variations. They influence the water cycle, provide fresh water and energy for human society, and contribute to the living basis of numerous ecosystems. Understanding the structure and dynamics of land ice requires knowledge of its mass density, which is essential for ice core climatology and estimates of mass balance components, such as mass loss, ice discharge and surface melt. We combine densely sampled fiber-optic sensing data from strong serendipitous anthropogenic sources with Hamiltonian Monte Carlo sampling to extract direct seismic constraints on firn density (i.e. the transitional layer between fresh snow and glacial ice). Our approach avoids biases introduced by subjective regularization choices, does not require empirical scaling relations from seismic wave speeds to density, and provides reliable uncertainty estimates. We demonstrate that high-quality surface-wave overtone data can directly constrain density to around 100 m depth. Commonly used scaling relations from seismic wave speeds to density, however, fail to reproduce resolvable details of glacial density structure, and they tend to deviate from direct constraints on the order of ±10 %. Consequently, ice mass inferred from seismic wave speed may be incorrect by a similar amount.

We present preliminary results of ambient seismic noise monitoring near the deep geothermal reservoir at the Vendenheim site north of Strasbourg in France. From November 2019 to mid 2021, various operations led to an intense induced seismic swarm with several events of magnitudes above 3.0Mlv. This crisis is also characterized by the presence of an isolated swarm ~5km south of the geothermal site as well as the occurrence of the maximum magnitude event (3.9Mlv) 6 months after the cease of injection tests. Understanding these remote and delayed triggering mechanisms is essential for the successful development of future deep geothermal projects. We use ambient seismic noise correlations betweens pairs of sensors from a composite network of 137 permanent and temporary stations in the area. In particular, we intend to monitor the evolution of the upper crust around the reservoir by studying velocity variations and coda waveforms decorrelation in different frequency bands.At high frequencies (1-3Hz), velocity variations appear to be correlated with fluctuations of the water table elevation. Strong decorrelations in waveform coda are also observed during holidays, suggesting changes in anthropogenic noise sources illumination. At low frequencies (3-6s), apparent variations of velocity and decorrelation with mainly an annual periodicity are observed, but could be associated with seasonal variations in the position of the sources of the second microseismic peak. This study shows that in order to observe temporal variation in the properties of deep geothermal reservoirs with ambient noise coda wave interferometry, it is necessary to understand and model variations in the subsurface layers and in the sources of ambient seismic noise.

On June 16, 2023 at 16h38 UTC, a moderate earthquake of magnitude MW=4.9 stroke western France south of Niort city, near the small village of La Laigne (Charente Maritime). The shaking has been widely felt in the whole NW France and macroseismic intensity (EMS98) of VII was reached at the epicenter. Such an event is relatively rare in continental France and represents the second largest event in the western France in the last century. The epicentral region is located at the northern termination of the Aquitaine basin where 300 m of Mesozoic sediments covers the variscan basement. The focal mechanism obtained from waveform inversion corresponds to a pure dextral strike-slip motion or a pure senestrial strike-slip motion along a EW or NS striking fault plane, respectively.The fault that ruptured on June 16 is not known. To gain insight on its characteristics, teams of Nantes (Osuna and LPG), of Strasbourg (EOST and ITES) and of the CEA deployed between June 17 and June 22, 2023 for approximately one month, a network of 3-components stations composed of 12 MEMS accelerometers, 104 five hertz geophones and 5 broadband velocimeters in a 40 by 30 km region around the epicenter, with a station inter-distance of approximately 4 km.We present is this study the first results derived from this unique experiment. In particular, we show that the aftershock sequence (more than 600 events recorded) highlights a planar rupture zone of about 5.4 km2, trending NS and strongly dipping to the East (75°), located between 2 and 5 km depth. Site effect analysis allows us to better understand large ground motion distributions over the area and their link with macroseismic intensities. The installed array also allows us to infer a preliminary 3D VS model of the region. We show the extent to which a dense temporary network is mandatory for studying the fine structure of the fault plane in a region where previous knowledge of active geological structures is limited.

Ambient seismic noise interferometry is a powerful tool to monitor changes in seismic velocities within the upper crust induced by various forcings. Several studies have shown that the dynamics of aquifers can generate significant seismic velocity variations, concealing more subtle variations linked to other phenomena. Here, we present a temporal and spatial analysis of subsurface seismic velocity variations over a portion of the Upper Rhine Graben in north-eastern France, hosting one of the largest watertable in Europe. We analyze 4 years of continuous seismic records between 2019 and 2023 from 144 permanent and temporary seismological stations, together with data from 195 piezometers from the APRONA observatory. Ambient seismic noise cross-correlations were calculated using horizontal and vertical components records, and we performed velocity variations in different frequency bands (ranging from 0.1 to 4 Hz) and lapse times. We systematically compared temporal variations in seismic velocities with ground water level variations. Overall, our results indicate a strong seasonality of seismic velocity changes above 1 Hz mainly in the ballistic surface waves time window and the beginning of the coda of correlations. This signature persists at lower frequencies, around 0.5 Hz, for longer times in the coda of correlations only. This suggests a possible influence of aquifer dynamics at greater depths. We spatially localised velocity changes above 1 Hz using coda waves sensitivity kernels and found patterns consistent with piezometric observations and the known limits of the water table.

Monitoring of geothermal reservoir deformation is essential for the normal development of the Enhanced geothermal system (EGS). Coda wave interferometry (CWI) with ambient noise is regarded as an effective and low-cost monitoring technique and draws more and more attentions. But the connection between the obtained CWI measurements and the undergoing physical changes of deep reservoir is still not so clear. In this study, we take Rittershoffen geothermal system (France) as a case study and conduct a series of forward simulations regarding the propagation of scattered wavefield through the deformed model considering acoustic-elastic effect based on Code_ASTER (mechanical loading) and SPECFEM2D (wave propagation). The simulations are based on a two dimensional numerical model with a scale of 12km (width)×20km (height), in which the upper reservoir model contains 8 layers to mimic Rittershoffen geothermal reservoir, the lower sub model with multiple circular inclusions is set to scatter the waves emitted from point source at bottom and produce scattered wavefield; two seismic stations are located at the top of the model. The model is first verified by reproducing the seasonal variation of relative wave velocity changes obtained from ambient noise cross-correlation functions (ANCCF) induced by the underground water table elevation changes. Based on the validated model, we study the effect of in-situ reservoir deformation on CWI measurements by modelling the hydraulic pressure increases on an open hole and the aseismic slip of an embedded fault which is based on the case of hydraulic injection of GRT-1 well, Rittershoffen. The result indicates the induced small reservoir deformation in both situations can be detected by CWI measurements, which helps us to have a better understanding about the connection between the obtained CWI measurements and the undergoing deformation of deep geothermal reservoir.

In 2022 a network of 23 seismometers and Distributed Acoustic Sensing (DAS) fibre optic cable were deployed on the North East Greenland Ice Stream (NEGIS). Using a combination of environmental seismology methods, we were able to gain a comprehensive understanding of the ice streams internal structure, giving insight into its past and present dynamics. From ambient noise recording, we utilise the 9-component correlation tensors associated with all station pairs. We derived dispersion curves for Rayleigh and Love wave group velocities with usable data in the frequencies from 1 to 25 Hz. These data are then inverted to obtain shear wave velocity measurements for the top 150 m of the ice stream using an MCMC approach. We reveal variations in the radial anisotropy for both the along and across-flow components.Alternative methods of passive seismology were explored, such as using the seismic signal from an airplane landing. The recorded signals by the surface DAS cable displayed exceptional clarity, revealing at least 15 visible wave propagation modes, including various Rayleigh and pseudo-acoustic waves within the frequency range of 8 to 55 Hz.Seismic While Drilling (SWD) methods utilising the noise from ice core drilling and cutting at NEGIS were investigated as an unconventional signal at the borehole camp. While not successful in this instance, recommendations for future deployments were provided to optimize the utilisation of these techniques.These methods collectively offer insight into the layering of snow, firn, and ice within the ice stream, indicating the presence of seismic anisotropy. Demonstrating the effectiveness of short-duration (2-3 weeks) seismic deployments in glaciology.

The COVID-19 pandemic led to restrictions on human mobility worldwide. In France, numerous phases of lockdowns and curfews were instituted in an attempt to limit the consequences of this pandemic. Through these various phases of restrictions, we analysed changes in human activity based on the study of ambient seismic noise level in metropolitan France. We propose a different approach to previous studies, studying variations in the seismic noise level between the pandemic years 2020 and 2021 with respect to 2019, before the pandemic, taken as a reference. We focused our work between 4 and 8 Hz, where human induced noise sources are significant. We took advantage of the wide instrumental coverage of metropolitan France to distinguish the effects of restrictions in urbanized and rural areas. Whether in urban or rural areas, the effects of lockdowns and curfews coincide with reductions in seismic noise levels. The magnitude of the noise level reduction is greater for the first than for the last lockdowns. We also observe a signature of curfew periods and analyse variations according to time of day and day of the week. Changes in road traffic during lockdowns and curfews are a major factor contributing to the observed variations in ambient seismic noise.

The grounding zones (GZ) of marine-terminating glaciers, where ice transitions from grounded to floating, experience strong mechanical changes in response to ocean tides. The spatial and temporal dynamics of these changes remain poorly documented, as they require multi-scale observations capable of resolving internal ice deformation. Here, we use seismic observations, collected across different years and various scales, coupled with GNSS observations, to evaluate the brittle deformation at the GZ and shear margins of the Astrolabe Glacier (East Antarctica, Terre Ad & eacute;lie). Automatic detection of icequakes reveals that seismic occurrence patterns vary with tides and sensor locations. At a multi-kilometer scale, we observe and locate numbers of large-duration magnitude events (average Md around 0.0) associated with shear margins. At a smaller scale (a few hundreds of meters), using a dense array of seismic nodes deployed across the GZ and GNSS observations of vertical ice motion, we capture numerous small-magnitude events (Md as low as -4.0) with spatial and time occurrences set by tide-modulated GZ dynamics. At rising tides, seismicity is dominant on the floating part of the glacier, while at falling tides, it is dominant over its grounded part. Based on these observations, we propose a conceptual framework for the dynamics of icequake activity at the glacier GZ, accounting for its three-dimensional tidal-induced bending, generating strain rates large enough to induce brittle deformation. Our findings highlight the value of multiscale seismic observations of outlet glaciers for capturing GZ space and time high-resolution seismic and displacement responses to tidal forcing.

Ice streams are major regulators of sea level change. However, standard viscous flow simulations of their evolution have limited predictive power due to incomplete understanding of involved processes. On the Greenland ice sheet, borehole fiber-optic observations reveal a brittle deformation mode that is incompatible with viscous flow over length scales similar to the resolution of modern ice sheet models: englacial ice quake cascades that are unobservable at the surface. Nucleating near volcanism-related impurities that promote grain boundary cracking, they appear as a macroscopic form of crystal-scale wild plasticity. A conservative estimate indicates that seismic cascades are likely to produce strain rates that are comparable in amplitude to those measured geodetically, thereby providing a plausible missing link between current ice sheet models and observations.

Cryoseismology, which records ice-induced seismic activity, is emerging as a powerful tool for studying the grounding zone - a critical spatio-temporal area where outlet glaciers grounded on the continent starts floating and interacting with the ocean underneath. The SEIS-ADELICE project supported by the French Polar Institute (IPEV) aims to characterise the dynamics of the Astrolabe glacier in Terre Adélie (East Antarctica), from its grounded part to its terminus in the ocean. Over the past 3 years, we deployed broad-band seismometers both at the grounding zone and on stable ice around the glacier, along with ocean bottom seismometers (OBS) close to the glacier terminus. In January 2023, the recording system was complemented by a dense array of 50 seismic nodes over the grounding zone. This allowed us to cover spatial scales from metres to several kilometres, providing a high-resolution observation of tidal forcing on the floating tongue and its repercussions on the glacier behaviour. The seismic records contain a wide range of signals, including icequakes, accepted to result from the brittle deformation of the ice. Although the seismic patterns at the different stations show clear modulation of icequakes by tidal cycles, their phasing with the tide depends on the location of the sensors, whether they are grounded or floating and on their distance from the active part of the glacier. This highlights the importance of the network typology and its proximity to the grounding line when characterising icequake occurrence patterns. Local icequakes detected at the grounding line exhibit a consistent occurrence during both rising and falling tides, with the peak activity observed during high tide. Source location analysis reveals that events are distributed across both the grounding line and the lateral shear zones of the glacier which are under strong stress from the ice-ocean interactions during tides.

In the Southern Hemisphere, the prevalence of oceans and the difficulty of access to land result in reduced coverage of seismological stations, limiting our detailed knowledge of Earth 's structures and of large earthquakes sources. This situation is exacerbated inside the antarctic continent, where only two permanent seismic stations are currently available (IU.QSPA at South Pole and G.CCD). The CCD station, built in early 2000s with state -of -theart surface instrumentation and located at the French -Italian Concordia base (75 degrees S, 123 degrees E), has been providing seismological data since 2008. However, it suffers from several problems: the vault is deformed by the hydrostatic pressure of the snow, the firn waveguide traps anthropogenic noise from the base causing strong noise below 1 s, and a coupling defect limits the performance above 30 s on the horizontal channels. To ensure the continuity of CCD and to improve its overall performance, we started in 2014 to plan the installation of a borehole seismometer at the site. In this article, we describe in detail this renovation of CCD and some examples of data analysis. The new borehole sensor shows that short -period disturbances are largely attenuated ( -20 dB at 0.1 s) compared to the surface installation and that the horizontal channels have a lower noise level at long periods ( -8 dB at 100 s). Data for all components are below the standard noise model between 0.1 and 0.2 s, which makes this sensor one of the quietest installations in the world for this bandwidth. For periods > 600 s we observe atmospheric pressure-related perturbations on the vertical component. Despite this problem, the new CCD borehole station is a success with better-than-expected performances at all periods < 600 s. The data produced are now distributed in the world 's data centers as G.CCD.20 and we encourage the scientific community to use the data for all studies requiring seismograms from Antarctica.

The GEOSCOPE observatory (Institut de physique du globe de Paris [IPGP] and École et Observatoire des Sciences de la Terre de Strasbourg, 1982) provides more than four decades of high-quality continuous broadband data to the scientific community. Started in 1982 with only two stations, the network has grown over the years thanks to numerous international partnerships. At present, 34 stations operate in 18 countries across all continents and on islands throughout the oceans, filling important gaps in global Earth coverage. Most of the first installed stations are still running today, allowing for long-term observations, and new sites are being prospected to further improve global coverage. Over the years, GEOSCOPE has contributed to defining today’s global seismology standards (data format, data quality level, instrumentation requirements), being the French contribution to the international effort for global seismic observations. The stations are instrumented with the best quality seismometers (from the very first STS-1 in the early 80s to the last STS-6A and Trillium T360 today) and digitizers (Q330HR and Centaur) to record with high fidelity the ground motions generated by all types of seismic sources. Real-time data are sent to the tsunami warning centers and both validated and real-time data are available at the IPGP, Epos-France and Earthscope data centers. The quality of GEOSCOPE data and metadata is ensured by daily and yearly validation that enables issue detection and mitigation. GEOSCOPE, in collaboration with the other global networks, has played and continues to play a crucial role in the study of Earth’s structure and global dynamics and the characterization of all types of seismic sources.

The recent calving of Astrolabe Glacier on the Adélie Coast (East Antarctica) in November 2021 presents an opportunity to better understand the processes leading to ice tongue fracturing. To document the fractures and rift evolution that led to the calving, we used the archive of Sentinel-2 optical images to measure the ice motion and strain rates from 2017 to 2021. The long-term evolution of the Astrolabe ice tongue is mapped using airborne and satellite imagery from 1947 to November 2021. These observations are then compared with measurements of sea-ice extent and concentration. We show that calving occurs almost systematically at the onset of or during the melting season. Additionally, we observe a significant change in the periodicity of sea ice surrounding Astrolabe Glacier in the last decade (2011–2021) compared to previous observations (1979–2011), which has resulted in a change in the Astrolabe calving cycle. Indeed, one can observe a decrease in the duration of sea-ice-free conditions during the austral summers after 2011 in the vicinity of the glacier, which seems to have favoured spatial extension of the ice tongue. However, the analysis of strain rate time series revealed that the calving of November 2021 (20 km2) occurred at the onset of sea-ice melting season but resulted from the glacier dislocation that took place suddenly in June 2021 in the middle of the winter. These observations indicate that while sea ice can protect and promote the spatial extension of a glacier ice tongue, its buttressing is not sufficient to inhibit rifting and ice fracturing.

Ambient noise interferometry has become a common technique for monitoring slight changes in seismic velocity in a variety of contexts. However, the physical origin of the resolved small velocity fluctuations is not well established for long-term seasonal effects. Here we propose a physical forward model of scattered waves in a deformable medium that includes acousto-elastic effect, which refers to non-linear elasticity with third-order elastic constants. The model shows that small pressure perturbations of a few kPa due to seasonal variations in the water table can induce seismic velocity changes compatible with those measured at the surface by ambient noise interferometry. The results are consistent with field observations near the deep geothermal site of Rittershoffen (France). They illustrate the capability in modeling the diffuse wavefield from scattering synthetic waves to reproduce ambient noise signals for monitoring environmental and/or deep reservoir signals. Monitoring the fine evolution of the Earth's crust either prior to catastrophic events such as earthquakes or landslides, or georesource exploitation, is an important objective for risk management. Ambient noise interferometry is one of the emerging tools for assessing the minute evolution of seismic velocities in the subsurface. However, the physical origin of the observed small velocity changes is not well established. Here we propose a physical model of scattered waves in a deformable medium that includes non-linear elastic effects, which are not conventionally considered. The model shows that small pressure perturbations of a few kPa due to seasonal variations in the water table can induce seismic velocity changes compatible with those measured at the surface by ambient noise interferometry. The results are consistent with field observations near the deep geothermal site of Rittershoffen (France). They illustrate the capability in modeling scattered synthetic waves to reproduce ambient noise signals. We develop an acousto-elastic model for seismic wave scattering in a deforming layered subsurface Stress fluctuations induced by seasonal water table variations are shown to be responsible for significant changes in seismic velocities The model is providing an interpretation tool for environmental monitoring signals obtained from ambient seismic noise

We analyse ambient-noise seismic data from 23 three-component seismic nodes to study firn velocity structure and seismic anisotropy near the EastGRIP camp along the Northeast Greenland Ice Stream (NEGIS). Using nine-component correlation tensors, we derive dispersion curves of Rayleigh and Love wave group velocities from 3 to 40 Hz. These velocity distributions exhibit anisotropy along and across the flow. To assess these variations, we invert dispersion curves for shear wave velocities (Vsh and Vsv) in the top 150 m of the NEGIS using a Markov chain Monte Carlo approach. The reconstructed 1-D shear velocity model reveals radial anisotropy in the firn, with Vsh 12 %-15 % greater than Vsv, peaking at the critical density (550 kg m-3). We combine density data from firn cores drilled in 2016 and 2018 to create a new density parameterisation for the NEGIS, serving as a reference for our results. We link seismic anisotropy in the NEGIS to effective and intrinsic causes. Seasonal densification, wind crusts, and melt layers induce effective anisotropy, leading to faster Vsh waves. Changes in firn recrystallisation cause intrinsic anisotropy, altering the Vsv / Vsh ratio. We observe a shallower firn-ice transition across the flow (approximate to 50 m) compared with along the flow (approximate to 60 m), suggesting increased firn compaction due to the predominant wind direction and increased deformation towards the shear margin. We demonstrate that short-duration (9 d minimum), passive, seismic deployments and noise-based analysis can determine seismic anisotropy in firn, and we reveal 2-D firn structure and variability.

We present an adaptation of the Backus-Gilbert method that enables (i) the incorporation of arbitrary prior knowledge and (ii) the solution of multiparameter inverse problems, providing a tunable balance between spatial resolution, inference errors and interparameter trade-offs. This yields a powerful approach for solving a class of inverse problems where the forward relation is linear or weakly nonlinear. The method rests on a probabilistic reformulation of Backus-Gilbert inversion and the solution of an optimization problem that maximizes deltaness while minimizing interparameter trade-offs. Applying the theory to multimode surface wave dispersion data collected by distributed acoustic sensing on the Northeast Greenland Ice Stream, we show that density in the firn layer may be constrained directly and without the need for scaling relations to depths of around ten metres, provided that dispersion data up to at least the third overtone of Rayleigh waves are available in the $\sim$10-50 Hz frequency band. The limiting factor that prevents the resolution of density at greater depth is data quality. Hence, progress on the direct inference of density could be made by repeated experiments or higher signal-to-noise ratios that would require better coupling and shielding of fibre-optic cables from wind and temperature fluctuations.

The versatility, cost-efficiency and easy deployment of seismic sensor nodes facilitate geophysical monitoring in environments that were previously inaccessible for instrumentation, and among them landslides and unstable slopes, most of the time located in remote mountains. Using nodes allows for the setup of dense arrays with sensor inter-trace distances that become compatible with the geometries and dimensions of the geological structures to image. This becomes particularly true for landslides which have complex 3D architectures (hummocky bedrocks, layering, multi-dimensional fractures, diverse geotechnical material, deep and perched aquifers and water circulations) and are shallow processes with respect to the classical investigation depths and sensitivity of most geophysical survey techniques.Here we develop a specific processing workflow to allow the computation of 3D shear-velocity models with Ambient-Noise-based tomography applied to dense arrays of seismic stations. The workflow is applied to a dataset acquired at the Viella shallow landslide (France) developed in altered schists and moraine deposits. We deployed 70 IGU-16HR-3C-5Hz SmartSolo sensors (EOST/PISE service) with inter station distances of 70 m for a period of 25 days.The processing consists in several steps, all of them being tuned to the specific case of shallow depths of investigation. In areas where only few strong (ML>4) earthquakes are triggered, with a low azimuthal distribution, surface-waves velocity fields are complex to estimate with earthquakes. Ambient noise cross-correlation tomography has the advantage of using the ambient noise to model the surface waves velocities by retrieving the interstation Green’s functions. The main hypothesis for retrieving the Green’s functions is a homogeneous noise-source distribution, which is never achieved in a natural environment. Therefore, data filtering and daily stacking are crucial to reduce the effect of non-uniform noise distributions and lead to consistent velocity models. Due to the noisy environment of Viella (torrential flows, farming activity, anthropogenic noise), several procedures were implemented to optimize the processing (reduction of the coherent noises in the processed data, use of a pseudo-topography to estimate as accurately as possible the inter-station distances and travel times). We then computed the dispersion curve diagrams for the surface waves on which we applied a strict selection to only keep the consistent part of the surface waves dispersion curves. The selection parameters were optimized for the Rayleigh and Love waves. Then, we inverted the inter-station travel times to compute group velocities maps at several frequencies. Finally, we proceed to a Markov-Chain-Monte-Carlo inversion of each of the dispersion curves extracted from the group velocity maps. We finally obtained a 3D shear velocity model, which is further combined with geological and borehole information in order to document the 3D structure.The objectives are to present the processing workflow developed specifically for shallow imaging and the retrieval of 3D heterogeneities; effects of the processing parameters will be discussed on the Viella dataset. The approach developed for Viella is generic and has been further applied to other geological processes (permafrost at the Chauvet rock glacier, Marie-sur-Tinée mudslide), and the models will be discussed.