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Abstract Pacific‐Panthalassa plate tectonics are the most challenging on Earth to reconstruct during the Mesozoic and Cenozoic eras due to extensive subduction, which has resulted in large (>9,000 km length) unconstrained gaps between the Pacific and Laurasia (now NE Asia) back to the Early Jurassic. We build four contrasted NW Pacific‐Panthalassa global plate reconstructions and assimilate their velocity fields into global geodynamic models. We compare our predicted present mantle structure, synthetic geoid and dynamic topography to Earth observations. P‐wave tomographic filtering of predicted mantle structures allows for more explicit comparisons to global tomography. Plate reconstructions that include intra‐oceanic subduction in NW Pacific‐Panthalassa fit better to the observed geoid and residual topography, challenging popular models of Andean‐style subduction along East Asia. Our geodynamic models predict significant SE‐ward lateral slab advections within the NW Pacific basin lower mantle (∼2,500 km from Mesozoic times to present) that would confound “vertical slab sinking”‐style restorations of imaged slabs and past subduction zone locations.
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EARA2024: a new radially anisotropic seismic velocity model for the crust and upper mantle beneath East Asia and Northwestern pacific subduction zones
SUMMARY We present a new 3-D radially anisotropic seismic velocity model EARA2024 of the crust and mantle beneath East Asia and the northwestern Pacific using adjoint full-waveform inversion tomography. We construct the EARA2024 model by iteratively minimizing the waveform similarity misfit between the synthetic and observed waveforms from 142 earthquakes recorded by about 2000 broad-band stations in East Asia. Compared to previous studies, this new model renders significantly improved images of the subducted oceanic plate in the upper mantle, mantle transition zone, and uppermost lower mantle along the Kuril, Japan, Izu-Bonin and Ryukyu Trenches. Complex slab deformation and break-offs are observed at different depths. Moreover, our model provides new insights into the origins of intraplate volcanoes in East Asia, including the Changbaishan, Datong-Fengzhen, Tengchong and Hainan volcanic fields.
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- PAR ID:
- 10541368
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Geophysical Journal International
- Volume:
- 239
- Issue:
- 2
- ISSN:
- 0956-540X
- Format(s):
- Medium: X Size: p. 914-935
- Size(s):
- p. 914-935
- Sponsoring Org:
- National Science Foundation
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