# Response of an active fault to hydraulic stress in the context of future geothermal development

Chrystel Dezayes, Julie Maury, Christian Crouzet, Églantine Husson, Jacques

Charroy, Jean-Luc Got, Théophile Guillon, Fabien Challeat

► To cite this version:

Chrystel Dezayes, Julie Maury, Christian Crouzet, Églantine Husson, Jacques Charroy, et al. Re-sponse of an active fault to hydraulic stress in the context of future geothermal development. World Geothermal Congress, International Geothermal Association, Jun 2026, Calgary (Alberta), Canada. hal-05232552

HAL Id: hal-05232552

https://brgm.hal.science/hal-05232552v1

Submitted on 23 Feb 2026

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons CC BY 4.0 - Attribution - International License
Response Of An Active Fault To Hydraulic Stress In The Context Of Future Geothermal Development

C. Dezayes¹*, J. Maury¹, C. Crouzet², E. Husson¹, J. Charroy², J.-L. Got², T. Guillon¹, F. Challeat³

BRGM¹*, USMB², SYANE³

c.dezayes@brgm.fr

**Keywords:** Fault, karst, Annecy, France, electro-magnetic, seismic velocity, HT modelling.

## ABSTRACT

Geothermal development in faulted basin environments presents specific challenges related to induced seismicity. This study investigates the hydro-mechanical behavior of the Vuache fault, located within the Annecy Basin (France), to assess the potential seismic hazard associated with future geothermal exploitation of the fractured and karstified carbonate aquifer. Based on an integrated dataset combining geological, geophysical, and hydrochemical observations, a 3D conceptual model of deep fluid circulation was constructed to guide numerical hydro-mechanical simulations. The results highlight a heterogeneous permeability structure controlled by three main fracture sets (NW-SE, NNE-SSW, ESE-WNW) and the presence of a conductive zone (~20–30 Ω·m) beneath Épagny at 1–1.5 km depth, spatially coincident with the 1996 Mw 5.3 earthquake area. Preliminary simulation outcomes suggest that significant fault reactivation would only occur under overpressures of approximately 10 Mpa, well above typical operational pressures expected in permeable carbonate systems. Consequently, the Épagny sector appears as a favorable target for medium-depth geothermal development. Further refinement of the geological and hydro-mechanical models is recommended to better constrain overpressure thresholds and fault stability.

## 1 INTRODUCTION

Geothermal exploitation in basin context with large faults (rifts, foreland basin,...) comes with seismic risks (eg. Basel, 2006-2009; Vendenheim, 2018-2021...). The development of geothermal energy in this context requires a better understanding of subsurface characteristics and seismic trigger mechanisms for derisking geothermal project development.

As part of the potential future exploitation of geothermal energy in the carbonate aquifer of the Annecy basin near the Vuache active fault (Thouvenot et al., 1998), the question of induced seismicity arises before any development takes place.

To address this question, a research project has focused on the hydromechanical behavior of this fault in order to constrain the seismic hazard and assess the reactivation/deactivation potential of the fault. Through numerical simulations, the objective of this project is to assess the impact of injection-extraction within the reservoir on the Vuache fault’s mechanical stability.

Prior to hydro-mechanical simulations, field geological and geophysical acquisitions on fracture networks, karstic morphology and deep geometry have been undertaken to bring information in order to better understand the reservoir behavior and its relationship with the adjacent active fault. Based on a 3D geological model (Dufour, 2019) and additional data such as spring chemistry, temperature survey, conductivity, flow rates..., a conceptual model of deep fluid circulation is proposed to help numerical modelling. This model also helps identify the target area. Hydromechanical simulations were undertaken in an attempt to replicate observables and test our understanding of large-scale fluid flow patterns and the response of the active Vuache fault to an injection coherent with the planned effect of geothermal exploitation.

## 2 GEOLOGICAL CONTEXT

### 2.1 Regional context

The External Alps, to which the study area belongs, comprise four main geological domains: from east to west, the external crystalline massifs (Belledonne massif), the subalpine massifs (Bornes, bauges massifs), the molasse basin and the internal Jura (Gros Foug; Figure 1).

The subalpine massifs (Bornes, Bauges) are thrust above the molassic basin, which constitutes a foreland flexural basin. The basin is filled with a detrital formation resulting from Tertiary erosion of the Alps, known as Molasse, consisting of marl and sandstone with a clayey limestone cement.
<figure><img src="image_2.png" /></figure>

Figure 1 – Location of the studied zone on the geological map (based on BRGM Haute-Savoie geological map, 1/250 000e). Names in black: anticlines; in blue: subalpine massifs; in yellow: internal Jura massif; in red: regional strike-slip faults. Dashed line corresponds to the cross-section location (Deville & Sassi, 2006). HU-2: Humilly borehole; LTA1: La Tailla 1D borehole; SV 107, SV 101 and CHY-1: other oil and gas vintage boreholes (Dufour, 2019).

The area of interest is located in the molassic basin at the level of a ramp anticline formed by the Montagne de la Mandallaz and the Montagne de l'Âge (Figure 1). These two ramp anticlines appear from the Molassic basin and are probably the result of a detachment at the base of the gypseous Upper Triassic (Figure 1). These two north-northeast/south-southwest trending folds bring to the surface karstified limestone of Urgonian age, corresponding to the Aptian and Barremian (Donze & Enay, 1972; Delaunay & Rampnoux, 1981).

These two anticlines are separated and offset by the sinistral Vuache fault, which is part of a series of NW-SE strike slip faults (Figure 1). This fault extends from the Haute Chaîne du Jura in the north-west to Lake Annecy in the south-east (Figure 1) and is currently active. A major earthquake occurred on 15 July 1996 with a magnitude of 5.3 and an estimated MSK intensity of VIII (Épagny earthquake; Thouvenot et al., 1998). A part of this fault outcrops along the southern edge of the Montagne de la Mandallaz. Sulphate thermal springs are present along this fault, at the foot of the south-east flank of the Montagne de la Mandallaz (Bromines spring). The age of this fault is still under discussion, but analysis of the seismic profiles tends to favour the hypothesis of an ancient fault rooted in the Permian basement, although this has not been definitively confirmed (Moscariello et al., 2014; De la Taille, 2015).
Also, several studies have highlighted deformation in upper Pleistocene sediments along the Vuache fault (Delaunay, 1981; Baize et al., 2011; De la Taille, 2015).

Historical and instrumental seismicity on the Vuache fault appears to be greater in its south-eastern part, near Annecy, than in its north-western part, where earthquakes are generally shallow and moderate. The deepest recorded earthquakes are located at a depth of 21 km. A 12km stretch of the Vuache fault, between La Balme-de-Sillingy and Sallenôves, is no recorded seismicity. The M5.3 earthquake of 15 July 1996 was located at a depth of between 1 and 3 km, in the Mesozoic limestone (Thouvenot et al., 1998).

The target for geothermal development is the Upper Kimmeridgian to Tithonian limestones. This formation is fractured and may be karstified, which increases its permeability and enables the initiation of the hydrothermal circulation that is essential for geothermal exploitation. The fluids present in these limestones could reach temperatures of ~ 60° to 70°C, at a depth of ~ 2 km (assuming an average geothermal gradient of 30 °/km, with the subsoil at a depth of around 10°C at 10 m in Annecy). The presence of the ramp anticline means that these formations are inclined, and the fluids present are under pressure. This system is like the hydrothermal system known at Aix-les-Bains, where the Chevalley borehole exploits pressurised water at a temperature of 72°C at a depth of 2.2 km in the Tithonian for thermal activity (Gallino et al., 2009; Hobléa et al., 2010).

## 2.2 Local geological investigations

The targeted limestone formation outcrops on The Montagne de la Mandallaz and the Montagne d'Âge, which are low ranges (highest point 923 m), completely wooded (Figure 2). A geological investigation for fractures and karstic morphology has been occurred in order to evaluate the reservoir properties.

<figure><img src="image_3.png" /><figcaption>Figure 2 – South part of the Montagne de la Mandallaz, cross-cutted by the Vuache fault, showing carbonate reservoir formations: Urgonian at the top of the mountain and Tithonian at the base.</figcaption></figure>

Various types of deep karst network in the Urgonian limestone have been observed:

- Surface karstic morphology, which highlight the fracture network.

- Deep karst network, including fossil and active network linked to variations in the base level of the water table.

There is medium density fracturing associated with karst. The density of fractures appears to be higher as you approach the Vuache fault, although there is no clear trend (Figure 3). Structural analysis of fractures shows three main families: NW-SE, NNE-SSW and ESE-WNW. The ESE-WNW family is the most common and is distributed throughout the sector. The NNW-SSE family is not uniformly present, nor is the NW-SE family. The NW-SE family is close to the direction of the Vuache fault and the other faults in the region.
<figure><img src="image_4.png" /></figure>

Figure 3 - Fracture direction rose diagrams and main directions observed (NW-SE in red, NNE-SSW in green and ESE-WNW in yellow). Color of outcrop points relative to fracture density (red: around 3 fractures/m; orange: around 2 fractures/m; green: around 1 fracture/m; blue: around 0.5 fracture/m). Rose diagrams at 10° intervals. Fracture pole density using the Kamb contouring method, interval: 2. Background: BRGM geological map (Donze et Enay, 1972). The Vuache fault is shown in red dashed lines and the Montagne de la Mandallaz and Montagne d'Âge thrusts in green dashed lines.

## 3 GEOPHYSICAL INVESTIGATIONS

Magneto-telluric (MT) data acquisition was performed from 2018 to 2024 over 48 sites distributed on an approximately 10 km x 10 km area NW to Annecy, along the Vuache fault. The aim of this data acquisition was to image the electrical resistivity at depth, in the Epagny area.

These MT data are highly affected by anthropogenic noise and make necessary the use of robust multivariate errors-in-variable (RMEV) processing approaches (Hering, 2019), based on Egbert (1997), for the processing of frequencies below 4Hz.

A 3D inversion including 48 full tensor impedances and 46 tippers was performed over 23 periods between 0.001 and 40s by using the FEMTIC (Usui, 2017) finite-element approach on a tetrahedral mesh, inverting also for galvanic distortion. The determination of regularization factors was made using an L-curve. Parameter variances ('error values') were adjusted closely from visual inspection. A very good fit was obtained to the data, yielding a model with a normalized RMS of 1.2. In order to assess uncertainty on resistivity estimates, an ensemble of models was inverted by inverting with different starting values of resistivity. The resulting ensemble showed good consistency, with final RMS values within 15% of that of the chosen model. A cell-wise analysis of the spread in resistivity values was defined based on the ratio P90/P10 of this distribution, which is represented alongside inverted resistivity values on Figure 4.
<figure><img src="image_5.png" /><figcaption>Figure 4 - Results of the 3D inversion of the apparent electrical resistivities. (1), left panel: Electrical resistivity parallel to the SVO-05 seismic profile (location Figure 3). Black dots figure the MT acquisition sites close to this profile. Color dots indicate the location of earthquakes (projections on the cross-section from 2.5km). Dot radius is proportional to magnitude. The biggest red dot is the Epagny 1996 earthquake. Colors of the dots indicate the days after mainshock. Dotted line: minor thrust faults (2), right panel: Estimation of the uncertainty using the spread of the resistivities computed for various initial models. Modified after Charroy et al., 2026.</figcaption></figure>

This value was considered as a practical measure of uncertainty on resistivity values related to starting model resistivity, corresponding to the width of the interval within which 80% of models of the above-mentioned ensemble are found. It is an imperfect assessment which doesn't take data sensitivity into account, and is dependent on the regularized inversion output, but can be obtained at a moderate computational cost of 21 times that of a single model in our case. It is very good at highlighting areas where tradeoffs can lead to a high level of variability in the dataset depending on starting resistivity, indicating higher uncertainty. Partial uncertainty thus defined is, as expected, generally greater over resistive bodies than conductive ones, but some resistive bodies just below a conductor/resistor interface can also be well resolved.

3D electrical resistivity model inferred by this approach allows retrieving the main geological features of the area. Mesozoic limestones and marly limestones are outlined by resistive bodies (Figure 4, about 1000 Ohm.m), whereas the Annecy-Epagny molasse basin corresponds to more conductive bodies (<200 Ohm.m). Minor thrust faults associated with the main thrusts are correlated with lateral deep resistivity variations (dotted lines on Figure 4a). These resistivity variations are interpreted as interruptions in the permeability of aquifers associated with karstified limestones where thrust faults intersect them. More conductive volumes (~20-30 Ohm.m) are imaged below Epagny, along the Vuache fault, at about 1km-1.5km below the surface and above the location of the M5.3 Epagny 1996 mainshock (Figure 4). The base of the conductive zone observed below Epagny may correlate with the interface between molasse and limestones. Given the lateral contrast observed at 1-1.5km depth across section SVO-05 (Figure 4), and an apparent greater concentration of aftershock hypocenters near this contrast zone, it is likely that this zone acts as an increased permeability zone. This could be associated with karsts in the Urgonian limestones. A coincidence of the southern boundary of the distribution of aftershock hypocenters, the presence of a thrust fault and that of a conductive/resistive lateral zone at depth is observed. This thrust fault, located below Epagny airport, could act as an impermeable interface limiting the conductive zone, likely porous and potentially permeable zone found at depth. This impermeable interface mostly prevents the diffusion of pressurized fluids that we interpret were linked with the generation of aftershocks following the Epagny 1996 earthquake.
# 4 DEEP FLUID CIRCULATION

## 4.1 Geological 3D model

Various previous studies have provided subsurface knowledge and enabled building of 3D geological models. The INTERREG GEOMOL project enabled the reinterpretation of seismic lines carried out in the 1970s and 1980s during various oil exploration projects and the creation of a 3D geological model of the Geneva molasse basin, particularly its French section, in order to estimate its geothermal potential (Capar et al., 2015).

More recently, in the area of interest around the Vuache fault, a detailed 3D geological model has been built based on the reprocessing of several vintage seismic lines, the calculation of seismic propagation velocities, the inversion of electrical resistivity measurements (ERT and MT), and the detection of earthquakes recorded by the permanent accelerometer network in Annecy (Dufour, 2019).

<figure><img src="image_6.png" /><figcaption>Figure 5 – 3D geological model of the studied area. Green: top of Urgonian carbonate formation; blue: top of Tithonian carbonate formation; purple: top of Triassic gypsum formation; red: Vuache fault; brown: Mandallaz thrust. X axis corresponds to the North (Dufour, 2019)</figcaption></figure>

While it is not perfect, this 3D geological model will be used as a basis for mechanical and hydraulic simulations. The geometry of the Mandallaz head could be improved by the field measurements, but it does not change the first simulations forecasted in the framework of this project.

## 4.2 Conceptual model of fluid flow

The two major identified reservoirs are lower Cretaceous carbonates (Urgonian) and upper Jurassic carbonates (Tithonian). Both are karstic and are investigated in the area of Geneva (Switzerland) by boreholes for geothermal exploitation (Guglielmetti et al, 2022). Moreover, two springs (Bain de Bromines and Bain de la Caille springs) show constant temperature, around 16-17°C and 24° respectively, all the year. Chemical analysis shows that these springs are a mix of mainly surface water and deep water, with a deep pole at 34°C. This analysis shows that the recharge areas would be those of the deep carbonate pole and surface water from 500-1000m above sea level.

Therefore, the Jura Mountains and the Saleve-Mandallaz Ridge, where karstified lower Cretaceous are exposed, are the main catchment areas. Water seeps and circulates in karstified and fractured lower Cretaceous and upper Jurassic carbonates, then discharges along the main fault structures (strike slip faults and thrusts) (Figure 6).
<figure><img src="image_7.png" /><figcaption>Figure 6 – Conceptual model of fluid flow in the studied area along two cross-sections: perpendicular (N-S) and parallel (E-W) to the Vuache fault.</figcaption></figure>

# 5 HYDRO-MECHANICAL MODELLING

## 5.1 Mechanical initial state

To infer the initial mechanical state before any geothermal activity is done, we built a numerical mechanical model. We used 3DEC™ software (Itasca consulting group, 2019) for simulations. The model dimensions are 11 by 12 by 4 km. The geometry of the model is based on the 3D geological model presented above. We integrate Vuache fault and the two thrusts explicitly as 2D mean planes. Lithology is integrated by varying the mechanical properties within the matrix depending on the corresponding lithology and within the Vuache fault. Since Annecy is a mountainous area, topography is considered in the model. To apply the boundary conditions, an encompassing box is added adding 1.8 km, on each side of the model, in horizontal directions. Velocity boundary conditions are imposed, based on bibliography (Delacou et al., 2008; Masson et al., 2019; Mathey et al., 2020).

A parametric study is realized to infer the most realistic boundary conditions and mechanical parameters based on seismicity. Figure 7-A shows the best shear displacement obtained, highlighting a negligible displacement below the topographic highest point that is coherent with observed seismicity located east of the mountain. The displacement deepens east of the mountain also coherent with events that can reach 3 to 3.5 km depth. However, we observe displacement (in red on Figure 7A) West of the mountain that is not observed in the seismicity observation and remains to be explained.

The obtained shear and normal stresses (Figure 7 B and C) highlight the impact of the Mandallaz and Age thrust, that increase the stress around them even if they remain elastic during our simulation (as expected for the absence of seismicity observed on these planes). We also observe an increase in normal stress directly below the Mandallaz mountain highlighting the topographic effects.

Some additional calculations are needed to fully understand the initial state, as geophysical observation infers an effect of natural hydraulic circulation on seismicity. Up to now we only considered the purely mechanical aspect, and this water effect may impact our results and explain the localization of the seismicity more to the east as conceptual fluid flow model (see above) suppose a fluid circulation from the mountain to the east.
<figure><img src="image_8.png" /></figure>

Figure 7 - Result of mechanical modelling to infer initial mechanical state on Vuache fault plane (NW-SE). A: shear displacement (meters) calibrated to reproduce strike slip behavior seen with 1996 earthquake. B: shear stress and C: normal stress on Vuache fault plane (Pa). Only areas with no boundary effects are shown. Width of model approximately 10km.

## 5.2 Hydro-mechanical (HM) modelling

The aim of HM model is to assess the potential for triggering geothermal exploitation on or near the Vuache. Buijze et al. (2019) shows that seismicity in hot sedimentary aquifers occurs mostly in granite targeted by EGS (Enhanced Geothermal System) with overpressure higher than 5 MPa. In permeable carbonates, exploitation generally occurs at lower overpressure (less than 5 MPa and closer to 1 MPa) and seismicity is less frequent even if it can happen. In most cases where it happens targeted reservoir was close to basement and seismicity occurred here (Buijze et al., 2019). In Annecy, we are in the second context, but we still need to check the induced seismicity potential as an active fault is close by. To do that we will use a hydro-mechanical model of 1.6 by 1.6 by 3 km including a single fault. We suppose there is some connection between the reservoir and the fault as inferred from the conceptual model and since the potential reservoir may be karstified, we suppose some channel lead to injection in the fault over an area of 100 m radius. Preliminary results are shown in Figure 8. If we suppose an overpressure of 1 MPa, nothing happens, the fault is stable. Seismicity occurs only if we suppose an overpressure of 10 MPa but this is a case that is not likely for future exploitation. These results are preliminary; we aim to use boundaries and initial mechanical conditions extracted from the initial mechanical state. This aspect will be considered in future work.

<figure><img src="image_9.png" /></figure>

Figure 8 - HM injection simulation. Results after 2 hours of 1 MPa or 10 MPa of overpressure (Pa). Cyan circles are earthquakes triggered by the injection.
# 6 CONCLUSIONS

This study brings important informations and knowledge for a future medium deep geothermal exploitation in Annecy area:

- Targeted carbonates are fractured and karstified, then contain a heterogenous permeability.

- Three main fracture directions can be used as permeability tensor: NW-SE, as the Vuache fault, NNE-SSW and ESE-WNW.

- A conductive zone (~20-30 Ohm.m) has been imaged below Epagny town, along the Vuache fault, at about 1-1.5km depth and above the location of the M5.3 1996 mainshocks.

- Meteoritic water seeps into the karstified and fractured carbonates outcropping on the point (Mandallaz, Age, Salève, Jura mountains) and circulates into low Cretaceous (Urgonian) and upper Jurassic (Tithonian), then discharges along the main faults (Vuache, Cruseilles faults, Mandallaz thrust).

- The preliminary results of generic HM simulation show that seismicity could occur if we suppose a 10 MPa overpressure. However, it will be not the case since generally exploitation overpressure is close to 1 MPa in permeable carbonates, and in all cases <5 MPa.

This study shows a more permeable/favorable zone above Epagny at around 1-1.5km depth for developing geothermal medium depth exploitation.

Results of preliminary simulations do not seem to indicate any seismicity in the case of normal exploitation. However, geological and HM models have to been improved to precise the limits of exploitation overpressure.

# Acknowledgements

This study has been funded by SYANE, public institution for renewable energy development, in the framework of a collaborative research project.

Authors would like to thank to the Communauté de Communes Fier & Usses to provide accessibility to spring and well data

Many other people have been involved in the project and authors would like to thank them for their help: François Crastes de Paulet, Stéphane Buschaert, Antoine Armandine les Landes (BRGM), Svetlana Byrdina, Andreas Junge, Volker Rath, Camila Riba-Pereyra, Philip Hering, Anneke Thiede, Laurent Métral (USMB).

# REFERENCES

Baize S., Cushing E. M., Lemeille F., Gelis C., Texier D., Nicoud G. & Schwenninger J.-L.: Contribution to the seismic hazad assessment of a slow active fault, the Vuache fault in the southern Molasse basin (France). Bull. Soc. Géol. Fr., **182**, 4, 347-365 (2011).

Buijze, L., van Bijsterveldt, L., Cremer, H., Paap, B., Veldkamp, H., Wassing, B. B., ... & Jaarsma, B.: Review of induced seismicity in geothermal systems worldwide and implications for geothermal systems in the Netherlands. Netherlands Journal of Geosciences, **98**, (2019) e13 doi: 10.1017/njg.2019.6.

Capar, L., Couëffé, R., Brenot, A., Courrioux, G., Dezayes, C., Gabalda, S., Lopez, S., Marc, S., Rambourg, D., Siméon, Y., Andenmatten, N., Clerc, N., Meyer, M., Rusillon, E. and GeoMol team: GeoMol – Évaluation des ressources naturelles dans les bassins d’avant-chaîne alpins pour une utilisation et une gestion durable du sous-sol – Zone Pilote Savoie-Genève. *Final report, BRGM / RP-64744-FR*, (2015) 218 p., 76 fig., 7 tabl., 9 ann.

Charroy, J., Byrdina, S., Got, J.-L., Rath, V., Metral, L., Riba-Pereyra, C., Tiede, A., Hering, P., Junge, A., Usui, Y.: 3D Finite-Element electrical resistivity modelling from MT measurements in the alpine foreland, Annecy, France: new insights in a seismogenic area, in prep. (2026)

De La Taille C.: Evaluation de l'activité tectonique quaternaire des failles du Jura méridional (France). PhD Thesis, 235 p. (2015).

Delacou, B., Sue, C., Nocquet, J. M., Champagnac, J. D., Allanic, C., & Burkhard, M.: Quantification of strain rate in the Western Alps using geodesy: comparisons with seismotectonics. *Swiss Journal of Geosciences*, **101**(2), 377-385 (doi: 10.1007/s00015-008-1271-3).

Delaunay A. & Rampnoux J.-P.: Les déformations au front des massifs des Bornes et des Bauges : analyse de la tectonique cassante de l'avant pays savoyard. Bull. Soc. Géol. Fr., **XXIII**, **7**, 2, 203-212 (1981).

Delaunay A.: Mise en évidence d'une phase tectonique quaternaire au front des chaînes subalpines savoyardes (France). Zeitschrift für Geomorphologie. Supplementband Stuttgart, **40**, 67-76 (1981).
Deville, E., Sassi, W.: Contrasting thermal evolution of thrust systems: An analytical and modeling approach in the front of the western Alps. *AAPG Bulletin, **90**, 6, (2006) 889-907.

Donze P. & Enay R.: Carte géologique de kla France (1/50 000) et notice explicative, feuille de Seyssel (677). Ed. BRGM, Orléans (1972).

Dufour, A.: Analyse de données sismiques et électriques pour l'estimation du potentiel géothermique d'Annecy, Haute Savoie. *Rapport de stage USMB, BRGM, Université Rennes 1 (2019).*

Egbert, G. D.: Robust multiple-station magnetotelluric data processing, Geophysical Journal International, 130(2), **475-496**, (1997) doi:10.1111/j.1365-246X.1997.tb05663.x

Gallino S., Josnin J.-Y., Dzikowski M., Cornaton F. & Gasquet D.: The influence of paleoclimatic events on the functioning of an alpine thermal system (France): the contribution of hydrodynamic-thermal modeling. *Hydrogeology Journal*, 17, 8, 1887-1900 (2009).

Guglielmetti, L.; Heidinger, M.; Eichinger, F.; Moscariello, A.: Hydrochemical Characterization of Groundwaters' Fluid Flow through the Upper Mesozoic Carbonate Geothermal Reservoirs in the Geneva Basin: An Evolution more than 15,000 Years Long. *Energies*, **15**, (2022) 3497. https://doi.org/10.3390/en15103497

Hering, P.: Advances in Magnetotelluric Data Processing, Interpretation and Inversion, Illustrated by a Three-dimensional Resistivity Model of the Ceboruco Volcano, Ph.D. thesis, Fachbereich Geowissenschaften/Geographie, Johann Wolfgang Goethe-Universität, Frankfurt am Main (2019).

Hobléa F., Gallino S., Audra P.: Genesis and functioning of the Aix-les-Bains hydrothermal karst (Savoie, France): past research and recent advances. Bull. Soc. Géol. Fr., 4, 315-326 (2010).

Itasca Consulting Group Inc, 3DEC-Three-Dimensional Distinct Element Code, Ver. 7.0, Minneapolis: Itasca, (2019).

Masson, C., Mazzotti, S., Vernant, P., & Doerflinger, E.: Extracting small deformation beyond individual station precision from dense Global Navigation Satellite System (GNSS) networks in France and western Europe. *Solid Earth*, **10**(6), (2019)1905-1920, doi: 10.5194/se-10-1905-2019.

Mathey, M., Sue, C., Pagani, C., Baize, S., Walpersdorf, A., Bodin, T., L. Husson, E. Hannouz, & Potin, B.: Present-day geodynamics of the Western Alps: new insights from earthquake mechanisms. *Solid Earth*, **12**(7), (2021) 1661-1681, doi: 10.5194/se-2020-196.

Moscariello, A., Gorin, G., Charollais, J., Russillon, E.: Geology of western Switzerland and nearby France in a Geo-Energy perspective. *19 th International Sedimentological Congress – Geneva- Field trip guidebook* (2014).

Thouvenot, F., Fréchet, J., Tapponnier, P., Thomas, J.-C., Le Brun, B., Menard, G., Lacassin, R., Jenatton, L., Grasso, J.-R., Coutant, O., Paul, A., & Hatzfeld, D.: The ML 5.3 Epagny (French Alps) earthquake of 1996 July 15: a long-awaited event on the Vuache Fault, Geophysical Journal International, **135**(3), 876-892 (1998), (doi: 10.1046/j.1365246X.1998.00662.x.

Usui, Y., Ogawa, Y., Aizawa, K., Kanda, W., Hashimoto, T., Koyama, T., Yamaya, Y., & Kagiyama, T.: Three-dimensional resistivity structure of Asama Volcano revealed by data-space magnetotelluric inversion using unstructured tetrahedral elements, Geophysical Journal International, **208**(3), (2017) 1359-1372, doi: 10.1093/gji/ggw459