Perturbational and nonperturbational inversion of Rayleigh-wave velocities

Perturbational and nonperturbational inversion of Rayleigh-wave velocities

The inversion of Rayleigh-wave dispersion curves is a classic geophysical inverse problem. We have developed a set of MATLAB codes that performs forward modeling and inversion of Rayleigh-wave phase or group velocity measurements. We describe two different methods of inversion: a perturbational method based on finite elements and a nonperturbational method based on the recently developed Dix-ty...

Nonperturbational surface-wave inversion: A Dix-type relation for surface waves

We extend the approach underlying the well-known Dix equation in reflection seismology to surface waves. Within the context of surface wave inversion, the Dix-type relation we derive for surface waves allows accurate depth profiles of shear-wave velocity to be constructed directly from phase velocity data, in contrast to perturbational methods. The depth profiles can subsequently be used as an ...

Rayleigh Wave Dispersion Curve Inversion: Occam Versus the L1-Norm

Shear-wave velocities under the Transantarctic Mountains and Terror Rift from surface wave inversion

Rayleigh wave data between 20 and 120s period recorded in the western Ross Sea region of Antarctica are inverted using the waveform inversion technique described in Passier and Snieder [1995]. From the data we extract estimates of local S velocity structure beneath the Transantarctic Mountains and the Terror Rift. The shear wave velocities found are up to 6 % slower than the PREM model at betwe...

Measurements of Mantle Wave Velocities and Inversion for Lateral Heterogeneity and Anisotropy 1 . Analysis of Great Circle Phase Velocities

Long-period (100-330 s) fundamental-mode Love and Rayleigh waves have been processed to measure the great circle phase velocities for about 200 and 250 paths, respectively. The observations are inverted for regionalized phase velocities and for an even-order harmonic expansion of the lateral velocity heterogeneity. The regionalized inversions achieve a maximum variance reduction of about 65% an...