Modified frequency–Bessel transform method for dispersion imaging of Rayleigh waves from ambient seismic noise

Higher mode information of surface waves is important in dispersion curve inversion for shear wave velocity structure. The frequency–Bessel (F-J) transform method is an effective tool for multimode surface wave extraction. The measured dispersion energy with the F-J method, however, would usually be contaminated by a type of ‘crossed’ artefacts at high frequencies. Xi et al. (2021) propose a modified F-J (MFJ) transform method in which the Bessel function is replaced by the Hankel function for dispersion analysis thereby avoiding the ‘crossed’ artefacts. Synthetic and real-world examples demonstrate the effectiveness of the proposed MFJ method in improving the accuracy of Rayleigh wave multimode dispersion measurements.

Figure 3. (a) Dispersion image generated by the F-J method. Two ‘crossed’ artefacts are labelled in the figure. (b) Dispersion image generated by the MFJ method.

This work has been done by Prof. Jianghai Xia’s group and published in Geophysical Journal International (a ZJUTOP journal). The first author Chaoqiang Xi was a PhD student when doing this work (now a lecturer). This study is supported by the National Natural Science Foundation of China under grant no. 41830103.

For more details:

 Xi, C., J. Xia, B. Mi, T. Dai, Y. Liu, and L. Ning, 2021, Modified frequency–Bessel transform method for dispersion imaging of Rayleigh waves from ambient seismic noise: Geophysical Journal International, 225, 1271–1280, doi:10.1093/gji/ggab008.