Robust Normal Mode Constraints on Inner-Core Anisotropy from Model Space Search
نویسندگان
چکیده
منابع مشابه
Robust normal mode constraints on inner-core anisotropy from model space search.
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 ...
متن کاملSupplementary Material to ’Robust Normal Mode Constraints on Inner Core Anisotropy From Model Space Search’ by C. Beghein and J. Trampert. Data
Data Two data sets were tested : the first one consisted of older normal mode splitting measurements (1, 2) (with 15 degree two and 7 degree four structure coefficients), and the second one consisted of the most recent splitting measurements that followed the great Bolivia and Kuril Islands earthquakes in 1994 (3–5) (with 22 degree two and 16 degree four data). The choice of data set one was ba...
متن کاملRegional 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...
متن کاملInner core attenuation anisotropy
We investigate the attenuation structure of the Earth's inner core and its relationship to the velocity structure globally and along various sampling directions, by studying the amplitude ratios and the differential travel times of the PKiKP–PKIKP and PKPbc– PKIKP phases. Our observations reveal that the amplitude ratios of these core phases, like the differential travel times, vary in both sam...
متن کاملInner core anisotropy inferred by direct inversion of normal mode spectra
The spectra of 25 inner-core-sensitive normal modes observed following eight recent major (Mw >7.5) earthquakes are inverted for anisotropic structure in the inner core, using a one-step inversion procedure. The mode data are combined with PKP(DF)^ PKP(AB) di¡erential traveltime data and the inner core is parametrized in terms of general axisymmetric anisotropy, allowing structure beyond restri...
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ژورنال
عنوان ژورنال: Science
سال: 2003
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.1078159