Missions

As part of the ANR XMAT (https://www.oca.eu/en/rech-geoazur/rech-geoazur-projets/299-geo-projets-recherche-phares/5184-anr-xmat-2024), carried out by Clément GANINO,detection of mantle anomalies for Moon and Mars using tidal deformation and the CITCOM/CITCOM-Moon terrestrial geophysical code: comparison with analytical approaches and non-linear rheologies

Activités

Three research axes:
1. The first aspect concerns comparison with analytical modelling, such as Love3D (Rovira-Navarro et al., 2024). These analytical models are very fast and can be an interesting tool for MCMC explorations to locate heterogeneities. However, calibration with full finite element integration is also required. This is why we propose to carry out this calibration by comparing the stress fields obtained with CitcomSVE and those obtained with Love3D.
2. The second line of research could be the introduction of Andrade rheology into CitcomSVE. So far, only the Maxwell rheology has been considered in the finite element software, but it has been shown that for bodies other than the Earth, nonlinear rheologies like Andrade's more realistically reflect dissipation in planetary bodies. Given that our project focuses mainly on the Moon, Mars and Mercury, this change is justified.
3. Finally, in collaboration with the group of Professor Zhong at Boulder University, we propose to introduce tidal deformation into the latest version of CitcomS, which takes compressibility into account. This will also allow us to model density anomalies, including the buoyancy module.

Compétences

experience in geophysics and numerical calculation

Contexte de travail

The objective of this project is to characterize the current 3D structure of the Moon, Mars and Mercury using tidal tomography developed at Géoazur, based on data from available space missions (Mars Express, MRO, Mars Odyssey, MGS) and future (Bepi-Colombo). The tool used for modelling the 3D structure is the finite element software CitcomSVE (Zhong et al., 2022). A first phase of the project has already been launched, with a PhD student working on the introduction into CitcomSVE of viscosity anomalies, shear modulus and density in the planetary mantle. The first results in terms of shear stress maps and Love numbers are promising.

The place of practice is the Géoazur laboratory on the CNRS Campus Azur, in Sophia Antipolis (Valbonne -06). Geoazur is a multidisciplinary research unit composed of geophysicists, geologists and astronomers uniting around major scientific issues: the telluric hazards (seismic, gravity and tsunami) and associated risks, the dynamics of the lithosphere and Earth imagery, the geodesy-metrology of the Earth and the near Universe. Geoazur currently has around 200 staff attached to four local authorities, two of them: the University Côte d'Azur - UCA and the Observatoire de la Côte d'Azur - OCA; two national authorities: the CNRS - UMR 7329 and the IRD - UR 082.