Regional Tomography targetting mantle plumes by waveform inversion: the case of la Réunion Island.

The mantle plumes, their origin, their surface signature (as hotspots) and their role inglobal geodynamics are considered as one of the "last frontier" challenges in Earthsciences. To first order, seimsic and volcanic activities are well understood by platetectonics. But mantle plumes cannot be explained by plate tectonics. Their birth,life and death play a fundamental role on the evolution of biological life on Earth,on plate tectonics reorganization. In that respect, La Réunion island is one of thelargest hotspot on Earth. Its birth, 65Ma ago, creating the Deccan volcanic traps inIndia (almost 1million km2) are associated with the Cretaceous-Tertiary boundaryand might have provoked the disappearance of more than 90% of life on Earth(including dinosaurs). However, the deep structure of this geological object and theexact geometry of volcanic plumes are still the subject of controversies. The useof seismic data acquired by the French-German RHUM-RUM experiment in theIndian ocean around La Reunion volcanic hostpot (2012-2016) and the collection ofbroadband seismic data by Incorporated Research Institution for Seismology (IRIS)enable us to investigate the deep structure of La Réunion Plume along its completetrack from its birth to its present stage in the Indian Ocean around La Reunion.The recent progress in inversion techniques enables a better resolution of thesestructures, by taking into account the full information of seismograms. We presentpreliminary results with an enhanced resolution in the transition zone (410-660 km). [ABSTRACT FROM AUTHOR]