Christophe Zaroli

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Home page of Dr. Christophe Zaroli

Lecturer at the University of Strasbourg
—
Maître de conférences (hors classe, HDR)

Teaching @ EOST:

  • Mathematics & computer science (applied to geophysics).

Research @ ITES:

  • Seismology / Seismic tomography
  • Development of new methods (SOLA–Backus–Gilbert tomography).
  • Seismic imaging of the Earth's interior at various scales

Watch my talk on SOLA tomography (Collège de France, Paris, 2021):

My research —recent years:

  • I have introduced and adapted the SOLA method to solve tomographic problems  (Zaroli, 2016, 2019; Zaroli et al. 2017), and named this SOLA tomography :-)
  • This represents a major step towards Inference-Oriented Seismic Tomography
  • The SOLA method (Subtractive Optimally Localized Averages; Pijpers & Thompson, 1992) is a variant of Backus & Gilbert's inverse theory (Backus & Gilbert, 1967, '68, '70).
  • Problems must be linear(-izable), but can be of large scale —and the model space can be treated using either a discrete (Zaroli 2016) or a continuous (Zaroli 2019) formalism.
  • If you'd like to learn more about it, you can download SOLA tomography in a nutshell (Zaroli, 2021, HDR)
  • If you'd like to experiment with SOLA tomography, you can download the codes made publicly available by Latallerie, Zaroli et al. (2025), which are based on the formalism developed by Zaroli (2016, Appendix A1).

Some advantages of SOLA tomography:

  • Inference-oriented SOLA tomography investigates properties of the Earth's interior
  • SOLA tomographic models (proxies) are accompanied with their resolution and uncertainty.
  • SOLA provides a direct control on model resolution/uncertainty.
  • NO a priori constraints on model parameters (but on model resolution).
  • SOLA models are free from averaging-bias effects, and can fit the data.
  • Data-kernels can be fully exploited (if no model space discretization).
  • Natural framework for tomographic-geodynamic comparisons.
  • Development of dVp and dVs models at comparable resolution (to infer R=dVs/dVp).
  • Development of dVsh and dVsv models at comparable resolution (to infer anisotropy).
  • And more... read our publications !

Peer-reviewed publications related to SOLA tomography (see 'Publications'):

  • 2016, Zaroli, GJI (download)
  • 2017, Zaroli, Koelemeijer, Lambotte, GRL (download)
  • 2018, Voronin & Zaroli, InTechOpen Book (download)
  • 2019, Zaroli, GJI (download)
  • 2020, Freissler (MSc student), Zaroli, Lambotte, Schuberth, GJI (download)
  • 2022, Latallerie (PhD student), Zaroli, Lambotte, Maggi, GJI (download)
  • 2023, Amiri (PhD student), Maggi, Tatar, Zigone & Zaroli, Seismica (download)
  • 2024, Restelli (PhD student), Zaroli, Koelemeijer, PEPI (download)
  • 2024, Freissler (PhD student), Schuberth, Zaroli, GJI (download)
  • 2025, Mag (PhD student), Zaroli, Koelemeijer, GJI (download)
  • 2025, Nouibat (postdoc), Zaroli, Lambotte, GRL (download)
  • 2025, Lima & Zaroli, GJI (download)
  • 2025, Latallerie (postdoc), Zaroli, Lambotte, Maggi, Walker, Koelemeijer, Seismica (download)
  • 2025, Amiri (PhD student), Tatar, Maggi & Zaroli, Tectonophysics (download)
  • 2025, Serra (PhD student), Zaroli, Lambotte, Koelemeijer, GJI (download)
  • 2026, Freissler (PhD student), Schuberth, Stotz & Zaroli, Proc. R. Soc. A. (download)
  • 2026, Latallerie (postdoc), Koelemeijer, Walker, Lambotte, Maggi & Zaroli, GRL (download)

Ph.D. thesis related to SOLA tomography (M.Sc. thesis & postdocs on SOLA tomo not listed here):

  • Ouattara, Y., 2019, University of Strasbourg/Abidjan
  • Dubois, F., 2020, University of Strasbourg
  • Latallerie, F., 2022, University of Strasbourg
  • Restelli, F., 2023, University of Royal Holloway/Oxford
  • Amiri, S., 2026 University of Strasbourg/Iran
  • Serra, F., 2026, University of Strasbourg
  • Mag, A., work in progress, University of Oxford
  • Freissler, R., work in progress, University of Munich (LMU)
  • Schneider, A., work in progress, University of Munich (LMU)
  • Mojicaboada, M., work in progress, University of Oxford

Example of SOLA tomography:

  • Global tomographic model SOLA-Z16 — available on SubMachine (web-based tools for exploring models).
  • This image (HAL), of SOLA-Z16, shows 3-D positive S-wave velocity anomalies (%) in mid lower-mantle: