Premium
Outer core density heterogeneity and the discrepancy between PKP and PcP travel time observations
Author(s) -
Soldati G.,
Boschi L.,
Piersanti A.
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl016647
Subject(s) - mantle (geology) , cosmic microwave background , outer core , geology , core–mantle boundary , travel time , inner core , seismic tomography , geophysics , core (optical fiber) , astrophysics , geodesy , seismology , physics , optics , engineering , anisotropy , transport engineering
We derive 3‐D tomographic maps of the Earth's mantle, CMB and outer core, from seismic P, PcP, PKPbc, PKPdf travel time data, based on the bulletins of the International Seismological Centre (1964–1995), after source relocation by Antolik et al. [2001] and phase re‐identification by Engdahl et al. [1998]. Maps of the CMB derived independently from core‐reflected (PcP) or core‐refracted (PKP) phases are not well correlated. We attempt to explain this discrepancy, and study the radial coherence of whole‐Earth tomographic images, to identify possible trade‐offs between CMB undulations and velocity anomalies in the mantle or outer core. Imaged velocity anomalies in the lowermost mantle are anticorrelated with the topography of the CMB; likewise, imaged lateral heterogeneities in the outer core are correlated with the topography of the CMB. This, together with the study of Piersanti et al. [2001], suggests that the core anomalies might not be entirely fictitious.