Théa Ragon bio photo

Théa Ragon

Postdoc at Caltech - Earthquakes, faults and inverse problems


I am the GPS Chair’s Prize Postdoctoral Fellow at the California Institute of Technology. I completed my PhD in Geophysics at Géoazur, Université Côte d’Azur, in May 2019.

My research aims at better understanding the deformation of the shallow parts of the Earth on multiple temporal and spatial scales, from the displacement induced a few seconds to days before, during and after an earthquake to the long-term interaction of fault networks. I am particularly interested in modeling or simulating earthquakes and faults behavior.
These last few years, I focused on source estimation problems, using probabilistic approaches to decipher the robust characteristics, or the uncertainties, of our models. I also use stochastic methods to study recent large earthquakes. Finally, I am also interested in how faults interact with each other and how their geometry impacts the deformation.

You can find me in my office in the Seismological Laboratory building:
Office 262 | South Mudd building
Caltech Seismo Lab | GPS Division
1200 E. California Blvd., 252-21 | Pasadena, CA 91125, USA

You can also reach me via:
tragon (at)

Latest News

  • November 2020: Our work on Accounting for uncertain 3D elastic structure in fault slip estimates is now out in GJI.

  • November 2020: A. Nutz’s work on the Plio-Pleistocene sedimentation in West Turkana (Kenya, EARS): Paleolake fluctuations, paleolandscapes and controlling factors is now out in Earth Science Reviews.

  • October 2020: Alexis Nutz will present Plio-pleistocene paleoenvironments in West Turkana (East African Rift System, Kenya) at the GSA Meeting - 10/29 at 7:15pm.

  • September 2020: Our work on the stochastic view of the 2020 Elazığ Mw 6.8 earthquake (Turkey) is available as a Preprint

  • August 2020: Our work on Bayesian estimate of interseismic slip deficit of the East and North Anatolian faults (Turkey) is now published in GRL

  • July 2020: Our work on the impact of topography on slip estimates is now published in Tectonophysics. We notably show that topography can largely affect slip models even when using geodetic data only, and that zeroth-order corrections are not sufficient to account for induced biases. Link to journal

  • June 2020: Our session proposal for AGU 2020 has been accepted! Please consider submitting abstracts to S016 - Modeling and imaging complex earthquake ruptures, co-convened with Ryo Okuwaki, Wenyuan Fan and Dara Goldberg.

  • March 2020: Q. Bletery et al. propose a Bayesian estimate of interseismic slip deficit of the East and North Anatolian faults (Turkey). Preprint available!

  • February 2020: Our work on topography is now available as a preprint! Check it out: Impact of topography on static slip estimates Free access link

  • December 2019: Our work at the 2019 AGU Fall meeting:
    • Don’t miss our session on Resolving the Complexity of Earthquake Processes convened with Kurama Okubo, Ryo Okuwaki, Wenyuan Fan and Harsha Bhat. Oral session on Thursday morning 10:20 - 12:20, and posters on Friday morning!
    • I will present how early afterslip impacts our co-seismic and post-seismic models in the session T13D. Come have a look at my poster the Monday afternoon!
    • Leah Langer will present our work about the impact of topography on static slip estimates, in the same poster session.
  • October 2019: Alexis Nutz presented our work about the rifting of the northern Turkana Depression (Kenya, EARS), at the French Association of Sedimentologists annual meeting.