Artifacts in High-Frequency Passive Surface Wave Dispersion Imaging: Toward the Linear Receiver Array

Passive surface wave methods are non-invasive, low-cost, and robust approaches to image near-surface shear-wave velocity (Vs) structure using passive seismic sources. A clean and high-resolution dispersion image is critical for surface wave analysis. In practice, however, artifacts or aliasing are almost inevitable in passive surface wave dispersion measurements and seriously pollute the measured dispersion spectra. It is significant to clarify how they are generated, how they affect the dispersion measurement, and how they can be attenuated. We provide the first comprehensive review on artifacts that are frequently observed in high-frequency (>1 Hz) passive surface wave dispersion measurements and summarize them into two general groups: geometry-related artifacts and source-related artifacts. Mathematical derivations and numerical as well as field examples are presented to explain the underlying physics of various artifacts and explore potential solutions and guidelines to attenuate them before and after field observations. This work will help the reader understand the complexity of the measured dispersion spectra and lead to improvements on rapidly advancing passive surface wave methods.