Global Adjoint Tomography - Model GLAD-M25

Session: Full-Waveform Inversion: Recent Advances and Applications
Type: Oral
Date: 4/29/2020
Time: 02:30 PM
Room: 120 + 130
Description: 

We will present our second-generation transversely isotropic global model, named GLAD-M25, which is the result of ten quasi-Newton tomographic iterations with an earthquake database consisting of 1,480 events in the magnitude range from 5.5 to 7.2, an almost six-fold increase over the first-generation model. We calculated fully 3D synthetic seismograms with a shortest period of 17s 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 Frechet derivatives in 3D anelastic Earth models facilitated by a parsimonious storage algorithm. The simulations were performed on the Cray XK7 "Titan'' at the Oak Ridge Leadership Computing Facility. We quantitatively evaluated GLAD-M25 by assessing misfit reductions and traveltime and amplitude anomaly histograms in twelve measurement categories. We performed similar assessments for a held-out data set consisting of 360 earthquakes, with results comparable to the actual inversion.

Presenting Author: Wenjie Lei

Authors