Missions

The goal of this 18-month postdoctoral position is to investigate the seismological manifestation of contrasting modes seafloor spreading regimes across the global mid-ocean ridge system. This will involve a systematic re-analysis of mid-ocean ridge seismicity catalogs, including global (teleseismic) and regional seismic / hydro-acoustic datasets. The postdoctoral researcher will design and implement novel methodologies to characterize the statistical distribution of mid-ocean ridge earthquakes, quantify the associated energy release, identify clusters and mechanisms of interests and perform relative relocations on targeted event swarms. The seismogenic properties of ridge sections will be systematically compared to their long-term tectono-magmatic properties, which are encoded in seafloor bathymetry. A database of notable seismogenic events will be assembled and analyzed. The results will inform the development of new models that describe how seafloor spreading operates on short time scales.

Activities

⁃ Perform statistical analyses (assessing distributions, clustering analyses, propagating location and other uncertainties...) of mid-ocean ridge catalogs, using standard, Bayesian and machine learning techniques.
⁃ Implement methodologies that improve estimates of earthquake magnitudes and location in remote oceanic domains.
⁃ Characterize seafloor spreading regimes and estimate long-term tectonic strain in selected ridge sections based on bathymetric analyses.
⁃ Interpret the results in light of geological observations and mechanical models of seafloor spreading across time scales.
⁃ Writing and documenting codes for catalog analysis for open distribution
⁃ Communicating the results at international conferences and publishing them in international, open-access journals

Skills

⁃ Background in seismology, hydro-acoustics, data science, geodynamics, geophysics, statistics, Bayesian inference
⁃ Experience with statistical analyses and machine learning techniques
⁃ Programming in C / python / Julia or equivalent, and ideally some experience with high-performance computing
⁃ Familiarity with marine seismology or hydro-acoustics
⁃ Strong scientific writing and oral communication skills, and proficiency in English are required. French is optional

Work Context

The postdoctoral researcher will be employed by CNRS (Délégation Paris Centre), and carry out their research within Ecole Normale Supérieure's Geology Laboratory, a joint research unit bringing together CNRS researchers and ENS-PSL faculty members. The successful candidate will join the Deformation and Structures team, which specializes in the observation and modeling of tectonic processes, from grain to lithospheric scale, and from seismic cycles to the growth of major geological structures. The research will be conducted under the supervision of Jean-Arthur Olive. This research is part of ERC project SeaSALT (Seafloor Spreading on Short And Long time scales, PI: J.-A. Olive), which will involve a team of PhD students and post-docs working on different aspects of seafloor spreading (magmatism, tectonics, hydrothermalism) on a range of time scales, with observational and modeling approaches. The postdoctoral researcher will also benefit from a network of national and international collaborations to support the interpretation of seismological datasets, and their comparison with observations of active and long-term deformation at mid-ocean ridges.

Constraints and risks

N/A