Distribution of fine-scale mantle heterogeneity from observations of Pdiff coda
Bulletin of the Seismological Society of America
By: P.S. Earle and P.M. Shearer
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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.
| 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 |
| Google Analytic Metrics | Metrics page |