Regional Tomography of Mantle Plumes by Full Waveform Inversion: Targeting French Polynesia

Mid-plate volcanoes known as hotspots are thought to represent the surface signature of mantle plumes. Their origin and their role in geodynamics are among the unresolved challenges in the Earth sciences. Even though plate tectonics and mantle plumes were conceptualized at the same time, the latter cannot be explained by the former. Plumes' birth, life and death play a fundamental role in the evolution of life on Earth and in plate-tectonic reorganization. The Islands of French Polynesia are located in the region of the South Pacific Superswell, far from plate tectonic boundaries. French Polynesia comprises several volcanoes (Cook-Austral, Society and Marquesas), roughly aligned along a hotspot track. The deep structure and the geometry of the geology responsible for fueling these hotspots at the surface are still a subject of controversy. We investigate the question of a possible connection between low-velocity anomalies beneath French Polynesia and the Central Pacific Superplume (a Large Low Shear-Velocity Province). New data from Mobile Earthquake Recorder in Marine Areas by Independent Divers (MERMAID) instruments deployed in French Polynesia (2018-now) play an important role in answering these questions. We evaluate the regional resolving power of a global full-waveform inversion mantle model, and shed light on the likely contributions of MERMAID data as well as data from ocean-bottom deployments using a variety of data and model-space metrics