3-D Monte Carlo surface wave tomography. Issue 3 (4th September 2018)

• Record Type: Journal Article
• Authors: Zhang, Xin; Curtis, Andrew; Galetti, Erica; de Ridder, Sjoerd
• Is Part Of: Geophysical journal international. Volume 215:Issue 3(2018:Dec.)
• Page Start: 1644
• Page End: 1658
• Publication Date: 2018-09-04
• Subjects: McMC -- Tomography -- Surface wave; Geophysics -- Periodicals; 550
• DOI: 10.1093/gji/ggy362
• Languages: English
• ISSNs: 0956-540X

Abstract

SUMMARY: Seismic surface wave tomography is a tried and tested method to reveal the subsurface structure of the Earth. However, the conventional 2-step scheme of inverting first for 2-D maps of surface wave phase or group velocity and then inverting for the 3-D spatial velocity structure preserves little information about lateral spatial correlations, and introduces additional uncertainties and errors into the 3-D result. We introduce a 1-step 3-D non-linear surface wave tomography method that removes these effects by inverting for 3-D spatial structure directly from frequency-dependent traveltime measurements. We achieve this using the reversible jump Markov chain Monte Carlo (McMC) algorithm with a fully 3-D model parametrization. Synthetic tests show that the method estimates the velocity model and associated uncertainties significantly better than the conventional 2-step McMC method, and that the computational cost seems to be comparable with 2-step McMC methods. The resulting uncertainties are more intuitively reasonable than those from the 2-step method, and provide directly interpretable uncertainty on volumetrics of structures of interest.