← Back to Sessions

Full-waveform Tomography of Europe and Western Asia and Full-waveform Moment Tensor Inversions

Description: 

We present a continental-scale tomographic model of Europe and Western Asia of transverse isotropic seismic wavespeeds of the crust and mantle based on full-waveform inversion (FWI). A drastic increase in quantitity of high quality data in the region prompted to revisit the study area from previous inversion results. The model has been inverted for a minimum period of 18 s, where developments in hardware and data-driven methodologies in Computational Seismology decreased the compute costs to make a high-resolution continental-scale model. Work on this model is tied with testing the methodologies for future applications to other model domains.

Dynamic mini-batches facilitate to reduce the inverse problem to a subset of events in a greater data set. Model updates are therefore cheaper and faster, while allowing the inclusion of more data if needed during the inversion. Meshes are adapted to the Wavefield by elongating elements azimuthally, reducing the number of elements compared to a standard cartesian mesh, while preserving gridpoints and further reducing costs for a model update. The model starts from the current generation of the Collaborative Seismic Earth Model (CSEM2) and is inverted in a multiscale approach to avoid cycle-skipping and enable monotonic misfit reduction. Misfit optimization is based on time-frequency phase misfits while gradient optimization is done through trust-region L-BFGS. For the Forward and Adjoint Simulations, the Salvus Spectral-Element Solver is used.

Full-waveform moment tensor inversions have been run on the model. For this the observable is inverted with synthetics simulated at 18 s in a least-square inversion. We compare the resolution for inverted moment tensors between PREM and the Europe model and find that 3D Earth models exhibit higher moment tensor resolution. This gives further implications on how to proceed with creating FWI Earth models when inverting for shorter periods.

Session: Earth’s Structure from the Crust to the Core [Poster]

Type: Poster

Date: 4/16/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Carl

Student Presenter: Yes

Invited Presentation: 

Poster Number: 102

Authors