Abstract
Building on global adjoint tomography model GLAD-M15, we present transversely isotropic global model GLAD-M25, which is the result of 10 quasi-Newton tomographic iterations with an earthquake database consisting of 1480 events in the magnitude range 5.5 ≤ Mw ≤ 7.2, an almost sixfold increase over the first-generation model. We calculated fully 3-D synthetic seismograms with a shortest period of 17 s based on a GPU-accelerated spectral-element wave propagation solver which accommodates effects due to 3-D anelastic crust and mantle structure, topography and bathymetry, the ocean load, ellipticity, rotation and self-gravitation. We used an adjoint-state method to calculate Fréchet derivatives in 3-D anelastic Earth models facilitated by a parsimonious storage algorithm. The simulations were performed on the Cray XK7 'Titan' and the IBM Power 9 'Summit' at the Oak Ridge Leadership Computing Facility. We quantitatively evaluated GLAD-M25 by assessing misfit reductions and traveltime anomaly histograms in 12 measurement categories. We performed similar assessments for a held-out data set consisting of 360 earthquakes, with results comparable to the actual inversion. We highlight the new model for a variety of plumes and subduction zones.
Original language | English (US) |
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Pages (from-to) | 1-21 |
Number of pages | 21 |
Journal | Geophysical Journal International |
Volume | 223 |
Issue number | 1 |
DOIs | |
State | Published - Oct 1 2020 |
All Science Journal Classification (ASJC) codes
- Geophysics
- Geochemistry and Petrology
Keywords
- Computational seismology
- Seismic anisotropy
- Seismic tomography
- Wave propagation
- Waveform inversion