Improving the retrieval of high-frequency surface waves from ambient noise through multichannel-coherency-weighted stack

Seismic interferometry is becoming increasingly popular in urban areas due to its ability to retrieve high-frequency surface waves from abundant anthropogenic seismic noise, hence the need for advanced processing schemes in resolving complex environments. Liu et al. (2021) obtain the multichannel coherency by summing the local phase coherencies in a time window and propose the multichannel-coherency-weighted stack method for accelerating the retrieval of high-frequency surface waves. A synthetic test and a real-world three-component example demonstrate the superiority of the proposed method over both the linear stack and the phase-weighted stack methods in obtaining cleaner surface waves and more accurate dispersion measurements.

 Figure 2. Virtual shot gathers (top row) and dispersion images (bottom row) of Rayleigh waves from 4.5-hr vertical component data. The left-hand, middle and right-hand columns represent the results of linear stack method, phase-weighted stack method and the proposed method, respectively.

This work has been done by Prof. Jianghai Xia’s group and published in Geophysical Journal International (a ZJUTOP journal). The first author Ya Liu is a PhD student. This study is supported by the National Natural Science Foundation of China under grant no. 41830103 and the project of Nanjing Center of China Geological Survey under grant no. DD20190281.

For more details:

 Liu, Y., J. Xia, C. Xi, T. Dai, and L. Ning, 2021, Improving the retrieval of high-frequency surface waves from ambient noise through multichannel-coherency-weighted stack: Geophysical Journal International, 227, 776–785, doi:10.1093/gji/ggab253.