Effects of surface scattering in full-waveform inversion

摘要: In full-waveform inversion of seismic body waves, often the free surface is ignored on grounds computational efficiency.Asyntheticstudywasperformedtoinvestigatetheeffectsofthissimplification.Intermsofsizeandfrequency,the testmodelanddataconformtoareallong-offsetsurveyofthe upper crust across San Andreas fault. Random fractal variations are superimposed a background model with strong lateral and vertical velocity ranging from 1200to6800m/s.Syntheticdatawerecomputedandinverted forthismodelanddifferenttopographies.Afullyviscoelastic time-domain code was used to synthesize seismograms, viscoacoustic frequency-domain utilized invert them. The focused early arrivals, which dominated by P-waves but also contain P-Rayleigh wave conversions near-field receiver. Resulting waveform models show artifacts loss resolution neglecting in inversion, inversions stable, they still improve kinematic models. extent deterioration dependsmoreonthesubsurfacethanonthesurfacestructure. Inversion results were improved at no additional expense introducing weak contrast along staircase function above shotsandreceivers.