Brown, SP, Thorne, MS, Miyagi, L et al. (1 more author) (2015) A compositional origin to ultralow-velocity zones. Geophysical Research Letters, 42 (4). 1039 - 1045. ISSN 0094-8276
Abstract
We analyzed vertical component short-period ScP waveforms for 26 earthquakes occurring in the Tonga-Fiji trench recorded at the Alice Springs Array in central Australia. These waveforms show strong precursory and postcursory seismic arrivals consistent with ultralow-velocity zone (ULVZ) layering beneath the Coral Sea. We used the Viterbi sparse spike detection method to measure differential travel times and amplitudes of the postcursor arrival ScSP and the precursor arrival SPcP relative to ScP. We compare our measurements to a database of 340,000 synthetic seismograms finding that these data are best fit by a ULVZ model with an S wave velocity reduction of 24%, a P wave velocity reduction of 23%, a thickness of 8.5km, and a density increase of 6%. This 1:1 VS:VP velocity decrease is commensurate with a ULVZ compositional origin and is most consistent with highly iron enriched ferropericlase.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | ©2015. American Geophysical Union. All Rights Reserved. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | ultralow-velocity zones |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) |
Funding Information: | Funder Grant number NERC NE/H022473/1 NERC NE/K006290/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 21 Apr 2015 13:53 |
Last Modified: | 18 Aug 2015 00:38 |
Published Version: | http://dx.doi.org/10.1002/2014GL062097 |
Status: | Published |
Publisher: | American Geophysical Union |
Identification Number: | 10.1002/2014GL062097 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:84075 |