BRGM

BRGM (Bureau de Recherches Géologiques et Minières) is the French public institution of reference for Earth Sciences and is acknowledged within France as a leading authority on surface and sub-surface resources and risks. BRGM has three main activities: scientific research, support for government policy, and international cooperation and development assistance. Research activities in BRGM gather a large variety of competences in geosciences, such as environmental monitoring, site selection and characterization, predictive modeling, risk analysis and safety management. Other principal objectives are to make scientific data publicly available, as well as methodologies and tools that increase the understanding and management of the problems resulting from natural hazards and policies of territorial development.

Earthquake generation process is highly nonlinear and the physical parameters governing the natural system are difficult to constrain. Yet, natural seismicity exhibits some systematic statistical behavior (scaling laws, space and time clustering, foreshock-mainshock-aftershock sequences, susceptibiility to small perturbations). In the framework of ANR project PREMs (Predictability of Earthquakes and Mathematical Models), we aim to understand the physics behind these detectable observables.
The main purpose of this thesis is to consider how physics-based simulations can constrain seismicity. On one hand, recent laboratory experiences now provide high quality of microseismic catalogs under controlled conditions. On the other hand, physics-based models have been developed with various ingredients such as rate- and state-dependent friction, multi-scale heterogeneity in fault friction, spatial distribution of seismogenic faults, as well as various stress loading system. In this project, we first aim to start modelling the experimental scale, emphasizing on the question of predictability of the seismicity in controlled laboratory settings. In a second step, we hope to extend our model to the field scale. A highly motivated student is expected to work to:

• develop numerical method based on the boundary integral equation method.
• Carry out sensitivity tests in numerical modeling.
• Analyze the simulation results through statistical quantities.
• Participate to laboratory experiments
• Analyze laboratory and field seismicity catalogs

The PhD student will have a contract (36 months) with BRGM, and belong to the Unit “Impacts, monitoring and safety of underground uses” of the Decarbonated Energy Direction under the supervision of Hideo Aochi and Julie Maury. The main office is in Orléans, France. Besides, a part of this PhD. will be held at ENS Paris, under the supervision of Alexandre Schubnel. At LGENS, the PhD. student will belong to the Unit “Déformation et Structures”. Training courses will be also available in PSL, as well as within the doctoral school GRNE.

Selection by the supervisors and the BRGM should be carried out before submission to the ED (hopefully for the 19th May, 2025 or later). We start the selection process from the 28th April 2025 until the position is filled. The applications must include the following documents. 1) CV, 2) cover letter, 3) two names of reference, 4) transcript of grades (Bachelor’s + Master’s 1 & 2). The documents are sent to Hideo Aochi (h.aochi@brgm.fr).

BRGM: https://www.brgm.fr
LG-ENS: https://www.geologie.ens.fr/
Ecole Doctorale GRNE: https://ed398.sorbonne-universite.fr/
ANR PREMs: https://aochihi.github.io/anr-prems/