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Seismic attenuation structure of the top half of the inner core beneath the northeastern Pacific
Author(s) -
Iritani R.,
Takeuchi N.,
Kawakatsu H.
Publication year - 2010
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 - 10.1029/2010gl044053
Subject(s) - inner core , geology , seismology , attenuation , core (optical fiber) , geophysics , physics , optics
We present a 1‐D seismic attenuation model of the top 600 km of the inner core beneath the northeastern Pacific. We employ a waveform inversion method for attenuation parameters based on simulated annealing that enables us to analyze complicated waveforms contaminated by phase overlaps. The method also allows analysis of PKP(DF) in distant ranges where only single core phase is present. The resultant data set is about five times larger compared with our previous study. The inverted model shows a gradual increase of the attenuation from the ICB to 200–250 km depth that coincides with a gradual increase of the P‐wave velocity in the same depth range. The attenuation decreases from this depth range, and thus shows a peak around 200–250 km. A possible relation of these observations to the growth process of the inner core in the western hemisphere of the inner core is discussed.