A Hybrid Lamb Wave Tomography Method Combining Traveltime and Waveform Data

Abstract

Results of current research on acoustic wave traveltime-based Lamb wave tomography have generally reflected the varied trend of velocity in media. In order to utilize more wavefield information to obtain velocity variation at finer scales, a hybrid Lamb wave tomography technique borrowed from seismic wave inversion is used in present study. The new method combines advantages of acoustic wave traveltime and waveform tomography. The conventional traveltime tomography using ray tracing is used as the initial velocity model of acoustic wave-equation waveform inversion using finite difference modeling. The method can enhance the resolution of traveltime tomography and overcome the drawbacks of waveform tomography which is subject to run into the local minima. Experimental results show that the method is very effective for improving the resolution of traveltime Lamb wave tomography.