Missions

As part of the ANR Fluid2Slip project, the postdoctoral researcher will have the opportunity to choose between two missions:
• Mission 1: Improve new automated algorithmic schemes to quickly, efficiently and robustly detect and extract recorded geophysical signals related to earthquakes.
• Mission 2: Characterise the fluid content near the subduction fault (downgoing and upper plates) by tomographic inversion of S-wave velocity (joint tomography of shots and earthquakes, or P-to-S converted waves from shots).
The postdoctoral researcher will use data acquired in Ecuador on a 3D network of ocean bottom seismometers and land stations.

Activités

As part of Mission 1:
1. Implementation/adaptation of an effective system for rapid and robust storage and optimised processing of large quantities of collected data.
2. Development and improvement of algorithms for processing acquired geophysical data in order to detect and locate different types of seismic phenomena. Detailed classification of events: LFE, VLFE, tremors, repeaters, etc. Correlation with fluid circulation, deformation and slip mode.
3. Participation in events (workshops, conferences, etc.) related to the ANR Fluid2Slip, supervision of M1 and M2 internships, writing newspaper articles on the results obtained.

As part of mission 2:
1. Compilation of various existing datasets (picking files of local earthquakes and shots), recording of P-waves converted to S-waves on OBS, construction of an a priori model based on available tomographic grids and determination of inversion parameters.
2. Vp and Vp/Vs tomographic inversion, analysis and interpretation of results (Vp/Vs in relation to Vp and seismicity).
3. Participation in events (workshops, conferences, etc.) related to the ANR Fluid2Slip, supervision of M1 and M2 internships, writing newspaper articles on the results obtained.

Compétences

- Computer encoding
- Excellent written and oral communication skills
- Experience in manuscript writing is desirable
- Ability to work in a team

More specifically:

- For mission 1: knowledge of signal and image processing, machine learning (PyTorch or TensorFlow + NumPy/SciPy), statistical processing & data and results visualisation tools.

- For mission 2: knowledge of seismology, geophysics, seismic data processing, tomographic inversion of first arrival times

Contexte de travail

The successful candidate will work at the Géoazur UMR7329 laboratory in Valbonne (06), collaborating with I3S as part of Mission 2. The Géoazur laboratory is a multidisciplinary joint research unit affiliated to four institution (the CNRS, the Côte d'Azur Observatory, the IRD and the Université Côte d'Azur) and is composed of geophysicists, geologists and astronomers working together on major scientific issues: earthquakes (seismic, gravitational and tsunamis), associated risks, lithosphere dynamics, Earth imaging, geodesy-metrology of the Earth and the nearby Universe.
It comprises around 200 people (researchers, engineers, doctoral students, etc.).
It is spread over two sites: the Azur CNRS campus in Valbonne Sophia Antipolis and the Calern-Caussols site of the Côte d'Azur Observatory.
The I3S laboratory is a joint research unit that brings together research in information and communication sciences and technologies. It comprises around 300 people. In partnership with the CNRS and Inria, and through numerous industrial collaborations, I3S works on innovative research topics at the cutting edge of science and technology: ubiquitous systems and networks, digital biology and health, environmental modelling, interactions and uses.

The successful candidate will join the team: Marine Geosciences, Observations and Innovative Imaging, which focuses on scientific issues and data from the oceans and their continental margins, and comprises around 30 permanent and non-permanent researchers. The research will be conducted under the joint supervision of Mireille Laigle (laigle@geoazur.unice.fr), Jerome Lebrun (lebrun@i3s.unice.fr) and Audrey Galve (galve@geoazur.unice.fr), and in collaboration with ANR Fluid2Slip partners, notably in Brest (Ifremer), Paris (ISTep) and Karlsruhe (KIT).
The researcher will be part of the ANR Fluid2Slip project, which aims to determine the structures and image the circulation of fluids in the Ecuadorian subduction zone in order to determine their role in seismic and aseismic slip.