Mantle Downwellings and the Fate of Subducting Slabs: Constraints from Seismology, Geoid Topography, Geochemistry, and Petrology

King, Scott D.

doi:10.1016/b978-044452748-6.00122-x

Cited by 9 publications

(1 citation statement)

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“…[2] Subduction process is proved to be closely related to seismogenesis, magma generation and metamorphic transformations [e.g., King et al, 2007;Stern, 2002;van Keken and King, 2005]. Therefore, studying the seismic heterogeneity and anisotropy in subduction zones is of great importance in understanding the dynamic process within the Earth.…”

Section: Introductionmentioning

confidence: 99%

P wave anisotropic tomography of the Nankai subduction zone in Southwest Japan

Wang

Zhao

2012

Geochem Geophys Geosyst

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[1] The active subduction of the young Philippine Sea (PHS) plate and the old Pacific plate has resulted in significant seismic heterogeneity and anisotropy in Southwest (SW) Japan. In this work we determined a detailed 3-D P wave anisotropic tomography of the crust and upper mantle beneath SW Japan using $540,000 P wave arrival times from 5,249 local earthquakes recorded by 1095 stations. The PHS slab is imaged clearly as a high-velocity (high-V) anomaly which exhibits considerable lateral variations. Significant low-velocity (low-V) anomalies are revealed above and below the PHS slab. The low-V anomalies above the PHS slab may reflect the upwelling flow in the mantle wedge and the PHS slab dehydration, and they form the source zone of the arc volcanoes in SW Japan. The low-V zones under the PHS slab may reflect the upwelling flow in the big mantle wedge above the Pacific slab. The anisotropy in the crust and upper mantle is complex. In Kyushu, the P wave fast velocity direction (FVD) is generally trenchnormal in the mantle wedge under the back-arc, which is consistent with the corner flow driven by the PHS slab subduction. The FVD is trench-parallel in the subducting PHS slab under Kyushu. We think that the intraslab seismicity is a potential indicator to the slab anisotropy. That is, the PHS slab with seismicity has kept its original fossil anisotropy formed at the mid-ocean ridge, while the aseismic PHS slab has reproduced the anisotropy according to its current deformation.

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Section: Introductionmentioning

confidence: 99%