PhD (M/F) – Monitoring of induced seismicity in the Rhine Graben

Job Description

Thesis Subject

The Upper Rhine Graben (URG) hosts a growing portfolio of deep geothermal extraction operations, all involving subsurface fluid manipulation and carrying a risk of induced seismicity. Despite broad monitoring coverage, the elastic models (Vp, Vs, density) of the areas of interest for deep geothermal reservoir exploitation, lack the resolution needed for reliable event location, and catalogs built on classical first-arrival picking show poor reconciliation across independent relocation approaches. This PhD addresses both issues along three axes: (i) augmenting catalog observables with directional attributes extracted by polarization analysis and array processing; (ii) modeling complex seismic phases: reflections, conversions, guided waves under asymptotic theory (eikonal solvers); (iii) deploying up to 120 seismic nodes in critical areas, with potential access to DAS recordings, as local quality-control benchmarks. The expected outcomes are an updated 3D elastic model of deep reservoirs in the URG, a quality-controlled catalog with improved event locations, and a phase atlas of the related wavefield that directly supports seismic hazard assessment for ongoing and planned subsurface operations in the region.

Objectives
1. Identify, probe and model complex phases in the target area wavefield; use them alongside directional attributes to reassess catalog picking, improve event locations, and reduce the inter-method relocation inconsistency observed in existing catalogs (+ potential use of quarry blasts)
2. Update the 3D elastic model (Vp, Vs, density) of the target area at a resolution adequate for induced seismicity monitoring, by exploiting a broader range of seismic observables from available and new recordings.
3. Deploy and process a temporary dense seismic network in critical zones around the target area to provide high-resolution local constraints and serve as independent quality control for the results of 1 and 2.

Activities
• Compile and consolidate existing seismic records: BCSF-RéNaSS, the RG geothermal network and the Raspberry Shake stations from the ANR PrESENCE project.
• Compare existing relocalisation catalogues to assess their inconsistencies and identify target areas.
• Extract directional attributes (back-azimuth, angle of incidence, apparent velocity) via polarisation analysis and beamforming to enrich the catalogue.
• Model complex phases (reflections, P-S/S-P conversions, guided waves) using Eikonal solvers to detect pointing errors and relocate events.
• Use quarry shots, whose positions are precisely known, as constraints on the model.
• Implement slope tomography using the adjoint method to jointly invert the Vp/Vs/density model and the positions of the sources.
• Prepare and deploy a temporary dense network (up to 120 nodes) in critical areas, then process the data. Where possible, incorporate DAS recordings via fibre optics.
Calculate synthetic waveforms to assess the sensitivity of phases to reservoir geometry and elastic parameters.
• Compile the final quality-controlled catalogue, the updated 3D elastic model and the phase atlas.
• Disseminate the results: articles in peer-reviewed journals, national and international conferences, a public-facing summary for ITI GeoT, and the writing of the thesis.

Skills
Knowledge: seismology, inverse problems, signal processing
Expertise: seismic signal processing, scientific programming, scientific writing in English, oral communication
Personal qualities: rigour, analytical thinking, communication skills

Your Work Environment

The successful candidate will work at ITES UMR7063 (Strasbourg Institute of Earth and Environment) within the seismology group, as well as in the seismology group at ITI GeoT (Interdisciplinary Thematic Institute for Energy Systems Transition – https://geot.unistra.fr/). The entire project will be carried out as part of the PEPR Subsoil PC9 'Rhine Graben' project (https://www.soussol-bien-commun.fr/fr/chantiers-regionaux/geothermie-profonde-dans-fosse-rhenan). The PhD will be affiliated with the University of Strasbourg's ED413 doctoral programme in Earth Science (https://ed-terre-environnement.unistra.fr/fr).

Practical information:
Remote working available
75% reimbursement of public transport season ticket costs
Access to the staff canteen

The project is funded half by the PEPR sub-programme PC9 'Fossé rhénan' and half by the ITI GeoT (for which the funding secured is earmarked for a student).

Constraints and risks

Non

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions