France Lagroix¹, Diana Jordanova², Neli Jordanova³, Pierre Antoine⁴, Denis-Didier Rousseau⁵, Johanna Lomax⁶, Markus Fuchs⁶, Christine Hatte⁷, Maxime Debret⁸, Olivier Moine⁹, Samuel Neil Taylor¹ and Jessica L Till¹⁰, (1)Institut de Physique du Globe de Paris, Paris, France, (2)Geophysical Institute Bulgarian Academy of Science, Sofia, Bulgaria, (3)Los Alamos, NM, United States, (4)Laboratoire de Géographie Physique - Université Paris 1, Meudon, France, (5)CNRS - ENS, LMD, Paris, France, (6)JLU University Giessen, Giessen, Germany, (7)LSCE, Gif-Sur-Yvette, France, (8)Normandie Univ, UNIROUEN, UNICAEN, CNRS, M2C, Rouen, France, (9)Chapel Hill, NC, United States, (10)University of Iceland, Institute of Earth Sciences, Reykjavik, Iceland