CaltechAUTHORS
  A Caltech Library Service

Mapping Mantle Transition Zone Discontinuities Beneath the Central Pacific With Array Processing of SS Precursors

Yu, Chunquan and Day, Elizabeth A. and de Hoop, Maarten V. and Campillo, Michel and van der Hilst, Robert D. (2017) Mapping Mantle Transition Zone Discontinuities Beneath the Central Pacific With Array Processing of SS Precursors. Journal of Geophysical Research. Solid Earth, 122 (12). pp. 10364-10378. ISSN 2169-9313. http://resolver.caltech.edu/CaltechAUTHORS:20180207-124354490

[img] MS Word - Supplemental Material
See Usage Policy.

366Kb

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20180207-124354490

Abstract

We image mantle transition zone (MTZ) discontinuities beneath the Central Pacific using ~120,000 broadband SS waveforms. With a wave packet-based array processing technique (curvelet transform), we improve the signal-to-noise ratio of SS precursors and remove interfering phases, so that precursors can be identified and measured over a larger distance range. Removal of interfering phases reveals possible phase shifts in the underside reflection at the 660, that is, S^(660)S, which if ignored could lead to biased discontinuity depth estimates. The combination of data quantity and improved quality allows improved imaging and uncertainty estimation. Time to depth conversions after corrections for bathymetry, crustal thickness, and tomographically inferred mantle heterogeneity show that the mean depths of 410 and 660 beneath the Central Pacific are 420 ± 3 km and 659 ± 4 km, respectively. The mean MTZ thickness (239 ± 2 km) is close to global estimates and suggests an adiabatic mantle temperature of ~1,400°C for the Central Pacific. Depth variations of the 410 and 660 appear to be relatively small, with peak-to-peak amplitudes of the order of 10–15 km. The 410 and 660 are weakly anticorrelated, and MTZ is thinner beneath Hawaii and to the north and east of the hotspot and thicker southwest of it. The relatively small discontinuity topography argues against the presence of large-scale (more than 5° wide) thermal anomalies with excess temperatures over 200 K across the transition zone. The data used cannot exclude stronger thermal anomalies that are of more limited lateral extent or that are not continuous across the MTZ.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1002/2017JB014327DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/2017JB014327/abstractPublisherArticle
ORCID:
AuthorORCID
Yu, Chunquan0000-0001-8681-8572
Day, Elizabeth A.0000-0003-0432-5817
van der Hilst, Robert D.0000-0003-1650-6818
Additional Information:© 2017 American Geophysical Union. Received 13 APR 2017; Accepted 24 NOV 2017; Accepted article online 30 NOV 2017; Published online 26 DEC 2017. All broadband seismic waveforms were downloaded from IRIS DMC (Incorporated Research Institutions for Seismology, Data Management Center). The data set generated in this study is available upon request from the corresponding author. We thank C. Houser and an anonymous reviewer for constructive comments. M.d.H. was supported by the Simons Foundation and NSF-DMS 1559587, R.v.d.H. acknowledges a Royal Society Fellowship to support travel to Imperial College, and M.C. is a Schlumberger Visiting Professor at MIT.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Simons FoundationUNSPECIFIED
NSFDMS-1559587
Royal SocietyUNSPECIFIED
Subject Keywords:SS precursors; mantle transition zone discontinuities; Hawaiian hotspot; array analysis; curvelet transform
Record Number:CaltechAUTHORS:20180207-124354490
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180207-124354490
Official Citation:Yu, C., Day, E. A., de Hoop, M. V., Campillo, M., & van der Hilst, R. D. (2017). Mapping mantle transition zone discontinuities beneath the Central Pacific with array processing of SS precursors. Journal of Geophysical Research: Solid Earth, 122, 10,364–10,378. https://doi.org/10.1002/2017JB014327
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84722
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Feb 2018 00:13
Last Modified:08 Feb 2018 00:13

Repository Staff Only: item control page