Description du sujet de thèse

Earthquake prediction remains a major challenge due to the complexity of the underlying physics and the heterogeneous nature of the Earth's crust. However, some large earthquakes such as Tohoku (2011, Mw9.0), Kumamoto (2016, Mw7.0) and Noto (2024, Mw7.7), have been preceded by localized seismicity, suggesting the presence of precursory mechanisms. This PhD project focuses on two crustal earthquakes: Kumamoto (2016) and Noto (2024), both of which were preceded by foreshocks, though their sensitivity to transient stress perturbations remains poorly studied. The aim is to analyze long-term microseismicity (magnitude < 3 earthquakes) using Japanese seismic catalogs over 15–20 years. GNSS data will be used to detect slow deformation and explore correlations with seasonal or tidal loading. The candidate will apply Machine Learning and template matching techniques to enhance event detection and lower the magnitude of completeness. Repeating earthquakes will be studied to understand local loading evolution. The goal is to better constrain the pre-seismic phase and evaluate the influence of transient stresses on seismicity. This work will combine seismological and geodetic observations to improve our understanding of earthquake physics.
Skills:
Disciplinary Profile: Solid skills in mathematics, physics, signal processing, and autonomous in code developing, especially in Python and Matlab. Able to handle data and cure them. Extra-disciplinairy profile: Initiative, adaptability, ability to work independently and as part of a team. Communicative and working skills. Proficiency in English (reading, writing, oral communication).
Interested candidates must have a Master degree in Geophysics or Physics. They are invited to send a project-specific cover letter and a CV.
Short bibliography:
Beaucé, E., et al. (2023). Enhanced tidal sensitivity of seismicity before the 2019
magnitude 7.1 Ridgecrest, California earthquake. Geophysical Research Letters,
https://doi.org/10.1029/2023GL104375
Gardonio et al. (2019a). Seismic Activity preceding the 2011 Mw9.0 Tohoku earthquake,
Japan, analyzed with multidimensional template matching, JGR, 124, 6815-6831.
Kato, et al. (2016), Foreshock migration preceding the 2016 Mw 7.0 Kumamoto
earthquake, Japan, Geophys. Res. Lett., doi:10.1002/2016GL070079.
Yoshida, et al. (2023). Updip fluid flow in the crust of the northeastern Noto Peninsula, Japan,
triggered the 2023 Mw 6.2 Suzu earthquake during swarm activity. Geophysical Research Letters, https://doi. org/10.1029/2023GL106023

Contexte de travail

The Centre national de la recherche scientifique is one of the world's leading research institutions. To meet the major challenges of today and tomorrow, its scientists explore life, matter, the Universe and the workings of human society. Internationally recognized for the excellence of its scientific work, the CNRS is a benchmark in the world of research and development, as well as for the general public.
The thesis will take place within ISTerre laboratory, a joint Research Unit of Université Grenoble Alpes, CNRS, USMB, IRD and Université Gustave Eiffel, located 1381 rue de la Piscine 38400 Saint-Martin d'Hères and on the Bourget du Lac Science Campus. It is part of the Observatoire des Sciences de l'Univers de Grenoble (OSUG) and the PAGE research cluster of the Université Grenoble Alpes (UGA). It employs around 300 people and has an average annual budget of €7 million. It is organized around 10 research and service teams, with the scientific objective of studying the physics and chemistry of planet Earth, with a particular focus on coupling observations of natural objects with experimentation and modeling of the associated complex processes. ISTerre also carries out solid Earth observation missions, and hosts and maintains national fleets of geophysical instruments, as well as a data center.
The thesis will be carried out in the "Seismic Cycle and Transient Deformations Team", with 42 people (researchers, post-docs, engineers, PhD students).
The doctoral school will be Earth, Environmental and Planetary Sciences (STEP).
This thesis is funded by an ANR consortium that involves one applied geoscience institution Hideo Aochi (BRGM), two academic geoscience laboratory Alexandre Schubnel (LG-ENS), one laboratory of physics, François Pétrelis (LP-ENS) and one laboratory of mathematics, Nicolas Pétrélis (LMJL). In addition, the project will benefit the existing collaborations particularly with Japanese researchers, S. Ide (Univ. Tokyo,), A. Kato (ERI, Univ. Tokyo), T. Hatano (Univ. Osaka), T. Hori (Jamstec) to enhance all the aspect of the data analysis and numerical simulations. Funding is available to participate in international conferences (European Geophysical Union, Vienna) and/or workshops (Cargèse School 2026, Workshop on Swarms in Les Houches). Also to cover publication fees.
Benefits :
- annual vacation entitlement: 45 working days
- inter-company restaurant
- reimbursement of public transport costs (75%)
- mutual participation
- telecommuting
- cultural and sporting activities
- sports facilities

Contraintes et risques

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