The existence of radial anisotropy in Earth's upper inner core revealed from seismic normal mode observations
نویسندگان
چکیده
منابع مشابه
Regional variation of inner core anisotropy from seismic normal mode observations.
Earth's solid inner core is surrounded by a convecting liquid outer core, creating the geodynamo driving the planet's magnetic field. Seismic studies using compressional body waves suggest hemispherical variation in the anisotropic structure of the inner core, but are poorly constrained because of limited earthquake and receiver distribution. Here, using normal mode splitting function measureme...
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We present a three-dimensional model of the seismic anisotropy and texturing of iron crystals in the inner core. The form of the anisotropy changes suddenly at slightly less than half of the inner core radius. The outer part is composed of iron crystals of a single phase with different degrees of preferred alignment along the spin axis of the Earth. The inner part may be composed of a different...
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A technique for searching full model space that was applied to measurements of anomalously split normal modes showed a robust pattern of P-wave and S-wave anisotropy in the inner core. The parameter describing P-wave anisotropy changes sign around a radius of 400 kilometers, whereas S-wave anisotropy is small in the upper two-thirds of the inner core and becomes negative at greater depths. Our ...
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ژورنال
عنوان ژورنال: Geophysical Research Letters
سال: 2015
ISSN: 0094-8276
DOI: 10.1002/2015gl064326