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Distribution of fine-scale mantle heterogeneity from observations of Pdiff coda

Bulletin of the Seismological Society of America

By:
,
DOI: 10.1785/0120000285

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Abstract

We present stacked record sections of Global Seismic Network data that image the average amplitude and polarization of the high-frequency Pdiff coda and investigate their implications on the depth extent of fine-scale (~10 km) mantle heterogeneity. The extended 1-Hz coda lasts for at least 150 sec and is observed to a distance of 130??. The coda's polarization angle is about the same as the main Pdiff arrival (4.4 sec/deg) and is nearly constant with time. Previous studies show that multiple scattering from heterogeneity restricted to the lowermost mantle generates an extended Pdiff coda with a constant polarization. Here we present an alternative model that satisfies our Pdiff observations. The model consists of single scattering from weak (~1%) fine-scale (~2 km) structures distributed throughout the mantle. Although this model is nonunique, it demonstrates that Pdiff coda observations do not preclude the existence of scattering contributions from the entire mantle.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Distribution of fine-scale mantle heterogeneity from observations of Pdiff coda
Series title:
Bulletin of the Seismological Society of America
DOI:
10.1785/0120000285
Volume
91
Issue:
6
Year Published:
2001
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Bulletin of the Seismological Society of America
First page:
1875
Last page:
1881
Number of Pages:
7