Abstract
Surface wave methods are non-invasive, low-cost, and robust approaches
to image near-surface S-wave velocity (Vs) structure. In terms of the
energy source types, they can be classified in two groups: active-source
surface wave methods and passive-source surface wave methods. A clean
and high-resolution dispersion image is critical for the subsequent
dispersion curve picking as well as Vs inversion for either the
active-source surface wave methods or the passive-source surface wave
methods. However, aliasing or other artifacts are almost inevitable in
surface wave dispersion measurements in practice, and they can seriously
pollute the measured dispersion spectra. It is significant to figure out
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 surface wave dispersion
measurements, and summary them into three general types, including
artifacts from spare spatial sampling, artifacts from array response,
and artifacts from weak coherent signals. Both numerical and field
examples, as well as mathematic derivations, are presented to help
reader understand the generations of the various types artifacts and the
way to attenuate them. This work will help us understand the complex
components on the measured surface wave dispersion spectra, and lead to
potential improvements on dispersion measurements.