Postdoctoral Reasearch: Mapping of seismic scattering and absorption properties of Earth materials. Insights in the structure and dynamics of the continental crust. Application to seismic hazard assessment.
IRAP (Toulouse University) in the framework of SIGMA 2 project : www.sigma-2.net
SIGMA2 (www.sigma-2.net) is a research and development project aimed at improving both seismic hazard and ground motion assessment methods. The project is founded by a consortium of industrial companies operating in the energy sector: EDF (France), Pacific Gas & Electricity (USA), Swiss Nuclear (Switzerland), CEA (France), CEZ (Cech Republic), Orano (France), CRIEPI (Japan). Consortium partners share a common interest in improving seismic hazard assessment practices within an open collaboration framework.
SIGMA-2 research actions rely on the excellence and commitment of a large panel of international scientific partners, from public institutions/academics industry and consultancy.
In the framework of SIGMA2, EDF will support one Postdoc researcher located at IRAP (University of Toulouse, France) to foster research and development aimed at improving the understanding of ground motion
attenuation. The main goals of the project include mapping of spatial variations of attenuation at the European scale, as well as their physical interpretation.
The extreme variability of short period seismic ground motion amplitude and duration observed over a broad range of spatial scales (100m- 100km) is one of the fundamental sources of epistemic uncertainty in the evaluation of
seismic hazard. Among the physical processes that control the amplitude of seismic waves, attenuation is probably the most poorly understood and undetermined factor, even though it plays an important role in various “hot”
engineering seismology topics. For instance, attenuation is identified as the phenomenon controlling the “kappa” parameter, currently used by engineers to characterize the high-frequency content of ground motions. Deciphering
and quantifying the mechanisms at the origin of attenuation represents a current challenge in seismology. The objective of the proposed research is to develop a genuine tomographic approach to the mapping of seismic
scattering and absorption properties of Earth materials with applications to the structure and dynamics of the continental crust and seismic hazard assessment.
The methodology that has been developed by the hosting team in Toulouse is based on theoretical and numerical developments in the field of radiative transfer, a mathematical model relating the 3-D distribution of scattering and
absorption properties at depth to the spatio-temporal distribution of seismic energy. The goal of the Post-doc fellow will be to develop an inversion scheme to map spatial variations of attenuation from observed variations in
seismic energy envelopes characteristics. To carry out this task, she/he will elaborate upon existing codes that enable the calculation of intensity sensitivity kernels based on either Monte-Carlo or spectral techniques. The
inversion method will be applied to the mapping of scattering and absorption properties of the crust in Western Europe. This region has been very well instrumented: about 1300 permanent seismic stations (broadband
velocimeters and accelerometers) and 30 temporary experiments have been deployed since 1996 (∼1100 stations). Waveforms are already available through the European portal EIDA. Western Europe displays a broad
geological diversity, including old and recent mountain ranges, volcanic areas, subduction zones at different stages, and major active faults. We expect our tomographic approach to unravel key geological features and to
significantly improve our ability to predict the variability of seismic ground motions at the regional scale.
Post-doc position description We seek a candidate with a strong background in at least one of the following
fields: inverse theory, numerical modeling, wave scattering and some experience in seismic data processing. The successful candidate will be hosted at IRAP in Toulouse (http://irap.omp.eu) and will work in collaboration with P. Traversa, EDF, Aix en Provence; F. Cotton and M. Pilz, GFZ, Potsdam. Numerical developments will be performed on a local cluster and full-scale applications will be performed at the regional HPC center Calmip (https://www.calmip.univ-toulouse.fr/).
2 years position
Deadline for application : 30th April 2019