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  • Grade/Statut : Doctorante
  • Établissement : UCB Lyon
  • Téléphone : +33 (04) 72 44 58 03
  • E-mail : alice.adenis at ens-lyon.fr

    Thème(s) de recherche

  • We aim to build a 3-D attenuation model of Earth's upper-mantle from a unique dataset built by Debayle & Ricard (2012).The dataset consists of 375,000 Rayleigh-wave attenuation and velocity measurements for the fondamental mode and the five first harmonics between 40 and 240 s periods. First, attenuation measurements are processed to extract the effects of geometrical attenuation and of focusing and defocusing, in order to minimize the influence of errors on the seismic source, to avoid potentially incorrect data, and to cluster redondant measurements. Then, measurements are regionalized to obtain Rayleigh-wave maps for each mode and each period. The last step is the inversion of these maps to obtain the depth dependent attenuation. Eventually, we obtain QsADR17, a 3-D model of S-wave attenuation in the upper mantle.
  • QsADR17 is correlated with surface tectonics down to 200 km depth, with low attenuation under the continents and high attenuation under the oceans. High-attenuation anomalies are found under oceanic ridges down to 150 km depth, and under most of the hotspots at larger depth down to the transition zone. A large high-attenuation anomaly at 150 km depth under the Pacific ocean suggest that thermal plumes pound into the asthenosphere.
  • We also detect compositional heterogeneities at the base of the cratons and in active areas.