Volume 28, Issue 1
Heterogeneity Spectrum of Earth's Upper Mantle Obtained from the Coherence of Teleseismic P Waves

Vernon F. Cormier, Yiteng Tian & Yingcai Zheng

Commun. Comput. Phys., 28 (2020), pp. 74-97.

Published online: 2020-05

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  • Abstract

Fluctuations in log-amplitude and travel time of teleseismic P waves recorded by the EarthScope USArray are used to invert for the heterogeneity spectrum of P-wave velocity in a 1000 km thick region of the upper mantle beneath the array. These fluctuations are used to form coherence functions. Best fits to joint transverse coherence functions require a depth dependent heterogeneity spectrum, with peaks in narrow depth ranges. These peaks agree well with peaks predicted for the temperature derivative of seismic velocity from models of the chemistry and phase of silicate mineral assemblages appropriate for the upper mantle, correlating with the depths of phase changes. The results show that chemistry and phase act in concert with lateral and depth variations in temperature to produce the observed heterogeneity in seismic velocities in the upper mantle at spatial scales from 50 to 300 km.

  • Keywords

Stochastic tomography, geophysical inversion.

  • AMS Subject Headings

86A15, 86A22, 74J20

  • Copyright

COPYRIGHT: © Global Science Press

  • Email address

vernon.cormier@uconn.edu (Vernon F. Cormier)

yiteng.tian@uconn.edu (Yiteng Tian)

yzheng12@uh.edu (Yingcai Zheng)

  • BibTex
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  • TXT
@Article{CiCP-28-74, author = {F. Cormier , Vernon and Tian , Yiteng and Zheng , Yingcai }, title = {Heterogeneity Spectrum of Earth's Upper Mantle Obtained from the Coherence of Teleseismic P Waves}, journal = {Communications in Computational Physics}, year = {2020}, volume = {28}, number = {1}, pages = {74--97}, abstract = {

Fluctuations in log-amplitude and travel time of teleseismic P waves recorded by the EarthScope USArray are used to invert for the heterogeneity spectrum of P-wave velocity in a 1000 km thick region of the upper mantle beneath the array. These fluctuations are used to form coherence functions. Best fits to joint transverse coherence functions require a depth dependent heterogeneity spectrum, with peaks in narrow depth ranges. These peaks agree well with peaks predicted for the temperature derivative of seismic velocity from models of the chemistry and phase of silicate mineral assemblages appropriate for the upper mantle, correlating with the depths of phase changes. The results show that chemistry and phase act in concert with lateral and depth variations in temperature to produce the observed heterogeneity in seismic velocities in the upper mantle at spatial scales from 50 to 300 km.

}, issn = {1991-7120}, doi = {https://doi.org/10.4208/cicp.OA-2018-0079}, url = {http://global-sci.org/intro/article_detail/cicp/16829.html} }
TY - JOUR T1 - Heterogeneity Spectrum of Earth's Upper Mantle Obtained from the Coherence of Teleseismic P Waves AU - F. Cormier , Vernon AU - Tian , Yiteng AU - Zheng , Yingcai JO - Communications in Computational Physics VL - 1 SP - 74 EP - 97 PY - 2020 DA - 2020/05 SN - 28 DO - http://doi.org/10.4208/cicp.OA-2018-0079 UR - https://global-sci.org/intro/article_detail/cicp/16829.html KW - Stochastic tomography, geophysical inversion. AB -

Fluctuations in log-amplitude and travel time of teleseismic P waves recorded by the EarthScope USArray are used to invert for the heterogeneity spectrum of P-wave velocity in a 1000 km thick region of the upper mantle beneath the array. These fluctuations are used to form coherence functions. Best fits to joint transverse coherence functions require a depth dependent heterogeneity spectrum, with peaks in narrow depth ranges. These peaks agree well with peaks predicted for the temperature derivative of seismic velocity from models of the chemistry and phase of silicate mineral assemblages appropriate for the upper mantle, correlating with the depths of phase changes. The results show that chemistry and phase act in concert with lateral and depth variations in temperature to produce the observed heterogeneity in seismic velocities in the upper mantle at spatial scales from 50 to 300 km.

Vernon F. Cormier, Yiteng Tian & Yingcai Zheng. (2020). Heterogeneity Spectrum of Earth's Upper Mantle Obtained from the Coherence of Teleseismic P Waves. Communications in Computational Physics. 28 (1). 74-97. doi:10.4208/cicp.OA-2018-0079
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