Wave-equation Rayleigh-wave dispersion inversion using fundamental and higher modes

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

Wave-equation traveltime inversion

This paper presents a new traveltime inversion method based on the wave equation. In this new method, designated as wave-equation traveltime inversion (WT), seismograms are computed by any full-wave forward modeling method (we use a finitedifference method). The velocity model is perturbed until the traveltimes from the synthetic seismograms are best fitted to the observed traveltimes in a leas...

Rayleigh wave dispersion curve inversion via genetic algorithms and Marginal Posterior Probability Density estimation

Surface wave dispersion curve inversion is a challenging problem for linear inversion procedures due to its highly non-linear nature and to the large numbers of local minima and maxima of the objective function (multi-modality). In order to improve the reliability of the inversion results, we implemented and tested a two-step inversion scheme based on Genetic Algorithms (GAs). The proposed sche...

Fundamental and higher-mode Rayleigh wave characteristics of ambient seismic noise in New Zealand

[1] In order to use ambient seismic noise for mapping Earth’s structure, it is important to understand the spatiotemporal characteristics of the noise field. This study uses data collected during four austral winter months of 2002 to investigate New Zealand’s ambient seismic noise field in the double-ocean-wave-frequency range (0.1–0.3 Hz). It is shown via beamforming analysis that there are tw...

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...