Hemispherical anisotropic patterns of the Earth's inner core.
It has been shown that the Earth's inner core has an axisymmetric anisotropic structure with seismic waves traveling approximately 3% faster along polar paths than along equatorial directions. Hemispherical anisotropic patterns of the solid Earth's core are rather complex, and the commonly used hexagonal-close-packed iron phase might be insufficient to account for seismological observations. We show that the data we collected are in good agreement with the presence of two anisotropically specular east and west core hemispheres. The detected travel-time anomalies can only be disclosed by a lattice-preferred orientation of a body-centered-cubic iron aggregate, having a fraction of their [111] crystal axes parallel to the Earth's rotation axis. This is compelling evidence for the presence of a body-centered-cubic Fe phase at the top of the Earth's inner core.
Mattesini
Maurizio
M
Departamento de Física de la Tierra, Astronomía y Astrofísica I, Universidad Complutense de Madrid, E-28040 Madrid, Spain. mmattesi@fis.ucm.es
Belonoshko
Anatoly B
AB
Buforn
Elisa
E
Ramírez
María
M
Simak
Sergei I
SI
Udías
Agustín
A
Mao
Ho-Kwang
HK
Ahuja
Rajeev
R
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