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A semi‐global reference model for electrical conductivity in the mid‐mantle beneath the north Pacific region

2003; American Geophysical Union; Volume: 30; Issue: 4 Linguagem: Inglês

10.1029/2002gl016092

1944-8007

Hisashi Utada, Takao Koyama, Hisayoshi Shimizu, Alan D. Chave,

Geomagnetism and Paleomagnetism Studies

One‐dimensional electrical conductivity structure in the mid‐mantle of the one‐fourth of the Earth beneath the north Pacific Ocean was obtained by a semi‐global electromagnetic induction study. Electromagnetic response functions estimated from electric field variations measured by submarine cables and geomagnetic field variations obtained by magnetic observatories and long‐term observations sites were inverted into radially symmetric conductivity distribution by taking the distribution of land and ocean at the surface into account. As a most preferred model, a smooth conductivity‐depth profile was obtained with two abrupt increases that possibly correspond to the seismic discontinuities at 410 and 660 km.