Ambient Noise Array Tomography Using Regionalized Phase Velocities From Array-Based Methods

Abstract

With the advancement of dense seismic arrays, array-processing methods for ambient noise data have become highly effective in extracting high-quality broadband surface wave dispersion curves from ambient noise. Recent advancements in array data processing methods have enabled the extraction of multimode dispersion curves, offering improved constraints on deep Earth structures. However, these array-based methods often produce regionalized dispersion curves, and conventional phase velocity maps constructed by interpolating these dispersion curves typically have limited resolution, and display smooth images of phase velocities. In this study, we develop an array tomography method aimed at improving the resolution of ambient noise tomography by utilizing dispersion curves extracted through array-based data processing. To demonstrate the effectiveness of our method in enhancing tomography resolution, we construct fundamental-mode 2-D Rayleigh wave phase velocity maps by applying our approach to regionalized dispersion curves obtained from array-based methods in the western United States. By comparing our tomographic results with those from conventional array-based methods, we show that our method can produce more accurate and higher-resolution phase velocity maps. Additionally, our approach is versatile and can be applied to construct high-resolution 1-D and 2-D velocity structures using regionalized phase velocities obtained from various other array-based data processing methods.