Normal-mode and free-air gravity constraints on lateral variations in velocity and density of earth's mantle

Miaki Ishii, Jeroen Tromp

Research output: Contribution to journalArticlepeer-review

381 Scopus citations

Abstract

With the use of a large collection of free-oscillation data and additional constraints imposed by the free-air gravity anomaly, lateral variations in shear velocity, compressional velocity, and density within the mantle; dynamic topography on the free surface; and topography on the 660-km discontinuity and the core-mantle boundary were determined. The velocity models are consistent with existing models based on travel-time and waveform inversions. In the lowermost mantle, near the core-mantle boundary, denser than average material is found beneath regions of upwellings centered on the Pacific Ocean and Africa that are characterized by slow shear velocities. These anomalies suggest the existence of compositional heterogeneity near the core-mantle boundary.

Original languageEnglish (US)
Pages (from-to)1231-1236
Number of pages6
JournalScience
Volume285
Issue number5431
DOIs
StatePublished - Aug 20 1999
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General

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