Topographic effect in marine magnetotelluric data and implications to the electrical conductivity structure of the mantle beneath the Tristan da Cunha hotspot area in southern Atlantic

Kiyoshi Baba1, Jin Chen2, Marion D Jegen2, Hisashi Utada1, Janina Kammann3 and Wolfram H. Geissler4, (1)Earthquake Research Institute, The University of Tokyo, Tokyo, Japan, (2)GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany, (3)København Universitet, København, Denmark, (4)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Geophysics, Bremerhaven, Germany