Zongwei Jin

and 6 more

A comprehensive full-waveform inversion model of the crust and mantle covering nearly the entire tectonic domain of the western Pacific (FWP24) is developed by the using optimized many-core version of SPECFEM-GLOBE on the new generation Sunway supercomputer. Taking the global adjoint tomography model GLAD-M25 as the initial model, the three-component seismograms from 1,228 earthquakes recorded at 3,687 stations are employed in iterative gradient-based inversions for three period bands: 40-100s, 17-40s, and 10-60s. A total of 36 iterations are carried out using the conjugate gradient method to update the velocities of horizontally and vertically polarized P-waves and S-waves (Vph, Vpv, Vsh, and Vsv) in the FWP24 model. This process systematically reduces the phase difference between the synthetic and observed seismograms within the phase measurements. Compared with the existing inversion results, the FWP24 model realizes a wider, more continuous and higher resolution inversion range, including all subduction zones in the western Pacific (e.g., Kurile-Japan, Izu-Bonin-Mariana, New-Britanin-Solomon, New-Hebrides, Tonga-Kermadec, etc.). Furthermore, it reveals more detailed structures particularly in oceanic regions around the Philippine Sea Plate, the Caroline Sea Plate and the Ontong-Java Plateau by applying more seismic rays. Overall, the high-resolution and wide-range FWP24 model not only supports for the study of the deep structure of the mantle in the study area, but also offers reliable insights for the study of the subduction dynamics in the western Pacific.