TX2019slab: A New P and S Tomography Model Incorporating Subducting Slabs

Chang Lu, Stephen P. Grand, Hongyu Lai, Edward J. Garnero

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Large numbers of earthquakes occur in subduction zones that are marked by dipping, narrow high seismic velocity slabs. The existence of these fast velocity slabs can cause serious earthquake mislocation problems that can bias estimates of seismic travel time residuals. This can affect the recovery of subducting slabs in tomography as well as introduce significant artifacts into lower mantle structure in tomography models. In order to better account for known subducting slabs, we performed a new P and S wave joint tomography inversion incorporating a three-dimensional thermal model of subducting slabs in the starting model. In addition, velocity and source locations were inverted for simultaneously. Our new P and S models feature higher-amplitude subducting slabs compared with previous global tomography results. The S to P heterogeneity ratio based on the new tomography model indicates that thermal elastic effects alone cannot explain all the heterogeneities in the lower mantle. Much of the observed abnormal S to P heterogeneity ratio can be explained by anelastic effects, the spin transition, and phase transitions of bridgmanite to post-perovskite in the lower mantle.

Original languageEnglish (US)
JournalJournal of Geophysical Research: Solid Earth
DOIs
StateAccepted/In press - Jan 1 2019
Externally publishedYes

Fingerprint

tomography
Tomography
slab
slabs
lower mantle
Earth mantle
Earthquakes
earthquakes
Travel time
earthquake
mantle structure
perovskite
seismic velocity
phase transition
dipping
P waves
travel time
travel
Phase transitions
subduction zone

Keywords

  • Anelasticity
  • Earthquake Mislocation
  • Post-perovskite
  • Seismic Tomography
  • Spin Transition
  • Subducting Slab

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

TX2019slab : A New P and S Tomography Model Incorporating Subducting Slabs. / Lu, Chang; Grand, Stephen P.; Lai, Hongyu; Garnero, Edward J.

In: Journal of Geophysical Research: Solid Earth, 01.01.2019.

Research output: Contribution to journalArticle

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N2 - Large numbers of earthquakes occur in subduction zones that are marked by dipping, narrow high seismic velocity slabs. The existence of these fast velocity slabs can cause serious earthquake mislocation problems that can bias estimates of seismic travel time residuals. This can affect the recovery of subducting slabs in tomography as well as introduce significant artifacts into lower mantle structure in tomography models. In order to better account for known subducting slabs, we performed a new P and S wave joint tomography inversion incorporating a three-dimensional thermal model of subducting slabs in the starting model. In addition, velocity and source locations were inverted for simultaneously. Our new P and S models feature higher-amplitude subducting slabs compared with previous global tomography results. The S to P heterogeneity ratio based on the new tomography model indicates that thermal elastic effects alone cannot explain all the heterogeneities in the lower mantle. Much of the observed abnormal S to P heterogeneity ratio can be explained by anelastic effects, the spin transition, and phase transitions of bridgmanite to post-perovskite in the lower mantle.

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