DefVolc ( is a software for inverse modeling of volcano deformation data (InSAR, GNSS), whether the sources of displacement are fracture (fluid filled fracture or faults) or massive reservoirs. DefVolc is based on a 3D Boundary element method for elastic media combined with non linear inversions, based on near-neighborhood inversion algorithms. Topographies are taken into account as well as interactions between sources. Boundary conditions are stress changes. An on demand computation service is also available through this portal for registered users. To be able to register, you need a Project code. It can be obtained upon request by contacting Valerie Cayol ( Alternatively, if you want to run the inversions on your own cluster, simply register with the Project code "anonymous".


To run the DefVolc pre and post-processor, you will need a computer with linux x86-64 and a version of gmsh more recent than 2.10.1.

You will need to install matlab Runtime corresponding to matlab version R2022a (

To run inversions on your machine, you will need a cluster but you can also run them on UCA clusters.

Terms of use

In no event, shall the authors be liable for any claims, damages or other liability arising from, out or in connection with the use of DefVolc.

Citations and acknowledgments

When communicating results generated by DefVolc, one must quote the DefVolc tools :

Cayol, V., Yo Fukushima, Farshid Dabaghi, Olivier Bodart, Marine Tridon, Delphine Smitarello, Quentin Dumont, Jean-Luc Froger, Christelle Wauthier, Cyprien Cattelain, C. Gouinaux, DefVolc : tools for 3D inverse modelling of deformation data,

On must also cite the following publications :

Cayol, V., et F. H. Cornet, 3D Mixed Boundary Elements for Elastic Deformation Field Analysis, Int. J. Rock Mech. Min. Sci. & Geomech. Abstr., 34, 275-287, 1997.

Fukushima Y., V. Cayol and P. Durand, Finding realistic dike models from interferometric synthetic aperture radar data: The February 2000 eruption at Piton de la Fournaise, J. Geophys. Res., 110, B03206,doi: 10.1029/2004JB003268, 2005.

If using the "No interpenetration" feature for fractures, please quote :

Cayol V., Catry T., Michon L., Chaput M., Famin V., Bodart O., Froger J.L., Romagnoli C. (2014). Sheared sheet intrusions as mechanism for lateral flank displacement on basaltic volcanoes: Application to Réunion Island volcanoes. Journal of Geophysical Research Letters 119. DOI:10.1002/2014JB011139 .

If using the computer resources provided by University Clermont Auvergne, please acknowledge it in the acknowledgment section of the publication, with the following sentence :

" We are grateful to the Mesocentre Clermont Auvergne University ( for providing help and/or computing and/or storage resources."

User's manual

It can be downloaded once you have registered

Publications by our group

1. Smittarello D., Smets B., Barrière J., Michellier C., Oth A., Shreve T., Grandin R.,Theys N., Brenot H., V. Cayol, Allard P., Caudron C., Chevrel O., Darchambeau F., De Buyl P., Delhaye L., Derauw D., Ganci G., Geirsson H., Kamate Kaleghetso E., Kasereka Mahinda C., Kervyn M., Kimanuka Ruhiro C., Le Mevel H., Makundi J., Molendijk S., Namur O., Nguomoja I., Poppe S., Schmid M., Subira J., Wauthier C., Yalire M., d'Oreye N., Kervyn F., Syavulisembo Muhindo, A., Precursor-free eruption triggered by edifice rupture at Nyiragongo volcano, Nature , doi:10.1038/s41586-022-05047-8, , 2022.

2. Dumont Q., V. Cayol, J.-L. Froger, A. Peltier, A major destabilisation structure revealed by 22 years of satellite imagery at Piton de la Fournaise, Nat Commun 13, 2649, 2022.

3. Dumont Q., V. Cayol, J-L. Froger, Mitigating biased inversions resulting from viewing geometries in InSAR, Geophysical Journal International, 2021.

4. Shreve T., R. Grandin, D. Smittarello, V. Cayol, V. Pinel, Y. Morishita, What triggers caldera ring-fault subsidence at Ambrym volcano? Insights from the 2015 dike intrusion and eruption, Journal of Geophysical Research, 2021.

5. Smittarello, D., V. Cayol, V. Pinel, J.L. Froger, A. Peltier, Q. Dumont, Combining InSAR and GNSS to track magma transport at basaltic volcanoes, Invited publication at Remote sensing, 2019.

6. Smittarello, D., Cayol, V., Pinel, V., Peltier, A., Froger, J‐L., & Ferrazzini, V. Magma propagation at Piton de la Fournaise from joint inversion of InSAR and GNSS. Journal of Geophysical Research, 124, 1361– 1387,, 2019.

7. Tridon, M., V. Cayol, J−L. Froger, A. Augier, and P. Bachèlery, Inversion of coeval shear and normal stress of Piton de la Fournaise flank displacement, Journal of Geophysical Research:Solid Earth, doi: 10.1002/2016JB013330, 2016.

8. Froger J. L., V. Cayol, V. Famin, The March-April 2007 eruption of Piton de la Fournaise as recorded by interferometric data, In: P. Bachèlery, Lénat, J.-F., Di Muro, A., Michon, L. (Editors), Active Volcanoes of the Southwest Indian Ocean: Piton de la Fournaise and Karthala. Active Volcanoes of the World. Springer-Verlag Berlin and Heidelberg, 428p., ISBN 978-3-642-31394-3, 2016.

9. Froger J.-L., V. Famin V., V. Cayol, A. Augier, L. Michon, J-F Lénat, Time-dependent displacements during and after the April 2007 eruption of Piton de la Fournaise, revealed by interferometric data, J. Volcanol. Geotherm. Res., 296, p.55-68, doi:10.1016/j.jvolgeores.2015.02.014, 2015.

10. Wauthier, C., V. Cayol, B. Smets, N. d’Oreye, F. Kervyn, Magma pathways and their interactions inferred from InSAR and stress modeling at Nyamulagira Volcano, D.R. Congo, Remote Sensing, 7, 15179-15202, doi:10.3390/rs71115179, 2015.

11. Remy, D., Froger, J. L., Perfettini, H., Bonvalot, S., Gabalda, G., Albino, F., Cayol, V., Legrand, D., De Saint Blanquat, M., Persistent uplift of the Lazufre volcanic complex (Central Andes): New insights from PCAIM inversion of InSAR time series and GPS data. Geochemistry, Geophysics, Geosystems, 15, DOI: 10.1002/2014GC005370, 2014.

12. Bodart O., V. Cayol, S. Court, J. Koko, Fictituous domain method for fracture models in elasticity, Proceedings of the 18th European Conference on Mathematics for Industry, 2014.

13. V. Cayol, T. Catry, L. Michon, M. Chaput, V. Famin, O. Bodart, J. L. Froger, C. Romagnoli, Sheared sheet intrusions as mechanism for lateral flank displacement on basaltic volcanoes: Application to Réunion Island volcanoes, J. Geophys. Res., 119, doi:10.1002/2014JB011139, 2014.

14. Wauthier C., V. Cayol, M. Poland, F. Kervyn, N. d'Oreye, A. Hooper, S. Samsonov, K. Tiampo, B. Smets, Nyamulagira's Magma Plumbing System Inferred from 15 Years of InSAR, Geol. Soc. London Special Publications: Remote Sensing of Volcanoes and Volcanic Processes: Integrating Observation and Modelling, 380, doi:10.1144/SP380.9, 2013.

15. Wauthier, C., V. Cayol, F. Kervyn and N. d’Oreye, Magma sources involved in the 2002 Nyiragongo eruption, as inferred from an InSAR analysis, J. Geophys. Res., 117, doi:10.1029/2011JB008257, 2012.

16. Fukushima, Y., V. Cayol, P. Durand, and D. Massonnet, Evolution of magma conduits during the 1998–2000 eruptions of Piton de la Fournaise volcano, Réunion Island, J. Geophys. Res., 115, B10204, doi:10.1029/2009JB007023, 2010.

17. Michon L., V. Cayol, L. Letourneur, A. Peltier, N. Villeneuve, T. Staudacher, Edifice growth, deformation and rift zone development in basaltic setting: insights from Piton de la Fournaise shield volcano (Réunion Island, Indian Ocean). J. Volcanol. Geotherm. Res., 184, 14–30, doi:10.1016/j.jvolgeores.2008.11.002, 2009.

18. Peltier, A., Staudacher, T., Bachèlery, P., & Cayol, V.. Formation of the April 2007 caldera collapse at Piton de La Fournaise volcano: Insights from GPS data. Journal of Volcanology and Geothermal Research, 184(1-2), 152-163, 2009.

19. Peltier A., V. Famin, P. Bachèlery, V. Cayol, Y. Fukushima, T. Staudacher, Cyclic magma storages and transfers at Piton de La Fournaise volcano (La Reunion hotspot) inferred from deformation and geochemical data, Earth. Planet. Sci. Lett., 270, 2-4, 180-188, doi:10.1016/j.epsl.2008.02.042, 2008.

20. Green, D. N., J. Neuberg, and V. Cayol, Shear stress along the conduit wall as a plausible source of tilt at Soufrière Hills volcano, Montserrat, Geophys. Res. Lett., 33, L10306, doi:10.1029/2006GL025890, 2006.

21. Fukushima, Y., Cayol, V., & Durand, P. . Finding realistic dike models from interferometric synthetic aperture radar data: The February 2000 eruption at Piton de la Fournaise. Journal of Geophysical Research - Solid Earth 110(B3), 2005

22. Froger, J. L., Fukushima, Y., Briole, P., Staudacher, T., Souriot, T., & Villeneuve, N. The deformation field of the August 2003 eruption at Piton de la Fournaise, Reunion Island, mapped by ASAR interferometry. Geophysical research letters 31 (14), 2004.

23. Dieterich J., V. Cayol, and P. Okubo, Stress Changes Before and During the Pu`u `O`o-Kupaianaha Eruption, U.S. Geological Survey Prof. Paper, 1676, 187-201, 2003.

24. Dieterich, J., V. Cayol et P. Okubo, The use of earthquake rate changes as a stress-meter at Kilauea volcano, Nature, 408, 457-460, 2000.

25. Cayol, V., J. Dieterich., A. Okamura et A. Miklius, High Magma Storage Rates Before the 1983 Eruption of Kilauea, Hawaii, Science, 288, 2343-2346, 2000.

26. Cayol, V. and F.H. Cornet, Effect of Topography on the interpretation of the deformation field of prominent volcanoes - Application to Etna, Geophys. Res. Let., 25, 1979-1982, 1998.

27. Cayol, V., & Cornet, F. H.. Three‐dimensional modeling of the 1983–1984 eruption at Piton de la Fournaise Volcano, Réunion Island. Journal of Geophysical Research , 103(B8), 18025-18037, 1998.

28. Cayol, V., et F. H. Cornet, 3D Mixed Boundary Elements for Elastic Deformation Field Analysis, Int. J. Rock Mech. Min. Sci. & Geomech. Abstr., 34, 275-287, 1997.

Publications by other groups

1. Leeburn, J., C. Wauthier, E. Montgomery-Brown, J. Gonzalez-Santana, New insights on faulting and intrusion processes during the June 2007, East Rift Zone eruption of Kīlauea volcano, Hawai'i, J. Volcanol.y and Geotherm. Res.,Vol. 421,, 2022.

2. Novoa, C., Remy, D., Gerbault, M., Baez, J. C., Tassara, A., Cordova, L., ... & Delgado, F. (2019). Viscoelastic relaxation: A mechanism to explain the decennial large surface displacements at the Laguna del Maule silicic volcanic complex. Earth and Planetary Science Letters, 521, 46-59, 2019.

3. Conway, S., Wauthier, C., Fukushima, Y., & Poland, M. A retrospective look at the February 1993 east rift zone intrusion at Kīlauea volcano, Hawaii. Journal of Volcanology and Geothermal Research, 358, 241-251, 2018.

4. Wauthier, C., Smets, B., & Keir, D. Diking‐induced moderate‐magnitude earthquakes on a youthful rift border fault: The 2002 Nyiragongo‐Kalehe sequence, DR Congo. Geochemistry, Geophysics, Geosystems, 16(12), 4280-4291, 2015.

5. Beauducel F., and D. Carbone, A strategy to explore the topography-driven distortions in the tilt field induced by a spherical pressure source. The case of Mt. Etna, Geophys. J. Int., 201(3), 1471-1481, doi: 10.1093/gji/ggv076, 2015.

6. A.M. Oyen, C. Wauthier, N. d'Oreye, R.F. Hanssen, The 2007 rifting event in Northern Tanzania studied by C and L-band interferometry, European Center for Geodynamics and Seismology Blue Books, vol.29, 131 pp, 2010.

7. Takada, Y. and Y. Fukushima, Volcanic subsidence triggered by the 2011 Tohoku earthquake in Japan, Nature Geoscience, 6, 2013.

8. Fukushima, Y., Mori, J., Hashimoto, M., & Kano, Y. Subsidence associated with the LUSI mud eruption, East Java, investigated by SAR interferometry. Marine and Petroleum Geology, 26(9), 1740-1750, 2009.

9. Peltier, A., Staudacher, T., & Bachèlery, P. (2007). Constraints on magma transfers and structures involved in the 2003 activity at Piton de La Fournaise from displacement data. Journal of Geophysical Research: Solid Earth, 112(B3), 2007.

10. Peltier, A., Staudacher, T., Catherine, P., Ricard, L. P., Kowalski, P., & Bachèlery, P. Subtle precursors of volcanic eruptions at Piton de la Fournaise detected by extensometers. Geophysical research letters, 33(6) , 2006.

11. Beauducel, F., G. De Natale, F. Obrizzo, and F. Pingue. 3-D modelling of Campi Flegrei ground deformations: Role of caldera boundary discontinuities. Pure Appl. Geophys., 161:7, 1329-1344, 2004.

12. Beauducel, F., F.H. Cornet, E. Suhanto, T. Duquesnoy, and M. Kasser. Constraints on magma flux from displacements data at Merapi volcano, Java. J. Geophys. Res., 105:B4, 8193-8204, 2000.

13. Beauducel, F., P. Briole, and J.L. Froger. Volcano wide fringes in ERS SAR interferograms of Etna: Deformation or tropospheric effect? J. Geophys. Res., 105:B7, 16,391-16,402, 2000.

14. Beauducel, F., and F.H. Cornet, 1999. Collection and three-dimensional modeling of GPS and tilt data at Merapi volcano, Java.J. Geophys. Res., 104:B1, 725-736, 1999.

Release notes

Lastest update : March, 2021


This project has received funding from the French ministry of Research and Education and from the European Union Horizon 2020 project EUROVOLC (, under grant agreement No. 731070


Valerie Cayol : forward model, inversion, interface;

Yo Fukushima, Marine Tridon, Delphine Smittarello, Quentin Dumont, Christelle Wauthier : inversion;

Olivier Bodart, Jean-Luc Froger : forward model;

Cyprien Cattelain, Farshid Dabaghi, Christophe Gouinaux : interface;

Clément Dupland, Yannick Guehenneux : on demand computation and database administration;


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