Publication Date:
2015-05-03
Description:
Precursors to the core phase PKP are generated by scattering of seismic energy from heterogeneities in the mantle. Here, we examine a large global dataset of PKP precursors in individual seismograms and array data, to better understand scattering locations. The precursor amplitudes from individual seismograms are analysed with respect to the inner core phase PKIKP and mantle phase PP. We find and correct for a hemispherical asymmetry in the precursor/PKIKP amplitudes, resulting from inner corestructure. Using ray tracing, we locate scatterers in our array data and use these to infer scattering locations in the individual data. The scattering strength displays regional variation, however we find no relationship with long scale CMB velocity structure. Scattering is observed in all regions of data coverage, as are paths with no precursors. This indicates scattering occurs from various small scale heterogeneities, including but not limited to ULVZs or partial melt, and slabs.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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