| Abstract: | Earth‘s lowermost mantle has thermal, chemical, and mineralogical complexities that require precise seismological characterization. Stacking, migration, and modeling of over 10,000 P and S waves that traverse the deep mantle under the Cocos plate resolve structures above the core-mantle boundary. A small -0.07 ?? 0.15% decrease of P wave velocity (Vp) is accompanied by a 1.5 ?? 0.5% increase in S wave velocity (Vs) near a depth of 2570 km. Bulk-sound velocity [Vb = (V p2 - 4/3Vs2)1/2] decreases by -1.0 ?? 0.5% at this depth. Transition of the primary lower-mantle mineral, (Mg1-x-y FexAly)(Si,Al) O3 perovskite, to denser post-perovskite is expected to have a negligible effect on the bulk modulus while increasing the shear modulus by ???6%, resulting in local anticorrelation of Vb and Vs anomalies; this behavior explains the data well. |
| Genre: | Article |
| ProdID: | 70000519 |
| Citation Author: | Hutko, A. R.; Lay, T.; Revenaugh, J.; Garnero, E. J. |
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| Citation End Page: | 1074 |
| Citation Issue: | 5879 |
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| Citation Language: | English |
| Citation Larger Work Title: | Science |
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| Citation Search Results Text: | Anticorrelated seismic velocity anomalies from post-perovskite in the lowermost mantle; 2008; Article; Journal; Science; Hutko, A. R.; Lay, T.; Revenaugh, J.; Garnero, E. J. |
| Citation Start Page: | 1070 |
| Citation Volume: | 320 |
| Citation Year: | 2008 |
| Type: | citation/reference |
| Text: | Anticorrelated seismic velocity anomalies from post-perovskite in the lowermost mantle; 2008; Article; Journal; Science; Hutko, A. R.; Lay, T.; Revenaugh, J.; Garnero, E. J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1126/science.1155822 |
| Date Other: | Tue, 28 Sep 2010 23:09 -0500 |
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