Subduction of a buoyant plateau at the Manila Trench: Tomographic evidence and geodynamic implications

Jianke Fan, Dapeng Zhao, Dongdong Dong

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We determined P-wave tomographic images by inverting a large number of arrival-time data from 2749 local earthquakes and 1462 teleseismic events, which are used to depict the three-dimensional morphology of the subducted Eurasian Plate along the northern segment of the Manila Trench. Dramatic changes in the dip angle of the subducted Eurasian Plate are revealed from the north to the south, being consistent with the partial subduction of a buoyant plateau beneath the Luzon Arc. Slab tears may exist along the edges of the buoyant plateau within the subducted plate induced by the plateau subduction, and the subducted lithosphere may be absent at depths greater than 250 km at μ19°N and μ21°N. The subducted buoyant plateau is possibly oriented toward NW-SE, and the subducted plate at μ21°N is slightly steeper than that at μ19°N. These results may explain why the western and eastern volcanic chains in the Luzon Arc are separated by μ50 km at μ18°N, whereas they converge into a single volcanic chain northward, which may be related to the oblique subduction along the Manila Trench caused by the northwestern movement of the Philippine Sea Plate. A low-velocity zone is revealed at depths of 20-200 km beneath the Manila Accretionary Prism at μ22°N, suggesting that the subduction along the Manila Trench may stop there and the collision develops northward. The Taiwan Orogeny may originate directly from the subduction of the buoyant plateau, because the initial time of the Taiwan Orogeny is coincident with that of the buoyant plateau subduction.

Original languageEnglish
Pages (from-to)571-586
Number of pages16
JournalGeochemistry, Geophysics, Geosystems
Volume17
Issue number2
DOIs
Publication statusPublished - 2016 Feb 1

Keywords

  • Manila Trench
  • buoyant plateau
  • earthquakes
  • seismic tomography
  • subduction

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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