Hemispherical structure in inner core velocity anisotropy
نویسندگان
چکیده
منابع مشابه
Inner 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 and Rotation
■ Abstract This paper reviews recent research focused on the Earth’s inner core. Large inner-core traveltime anomalies and the anomalous splitting of core-sensitive free oscillations strongly suggest that the inner core is anisotropic. Initial models involved a simple, constant or depth-dependent cylindrical anisotropy at a level less than a few percent. Recent observations suggest that its eas...
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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...
متن کاملPKP travel times at near antipodal distances: implications for inner core anisotropy and lowermost mantle structure
Previous studies from PKP(AB^DF) differential travel times at large distances suggest that the central part of the inner core is very anisotropic. These differential times, however, can be affected greatly by strong heterogeneity in the lowermost mantle. Here we examine a unique data set of PKP travel times from global digital and analog stations at near antipodal distances, where the effects o...
متن کاملTomographic inversion for three-dimensional anisotropy of Earth’s inner core
Seismological studies generally suggest that the Earth’s inner core is anisotropic and the anisotropic structure changes significantly both laterally and with depth. Previous body-wave studies of the inner core have relied on ray tracing or waveform modeling using one-dimensional (1D) models. Here we present non-linear tomographic inversions of the inner core anisotropy using three-dimensional ...
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ژورنال
عنوان ژورنال: Journal of Geophysical Research
سال: 2011
ISSN: 0148-0227
DOI: 10.1029/2010jb007942