A Fast GUI-Based Tool for Group-Velocity Analysis of Surface Waves

Abstract

\n We present an interactive graphical tool for extraction of group-velocity dispersion curves of seismic traces for rapid manual picking of large amounts of data: a task commonly encountered in ambient-noise tomography. The program can be used for group-velocity analysis of surface waves from earthquakes and controlled source data as well as of Green’s functions from cross-correlated ambient-noise data. The presented tool is especially suited to datasets in which automatic picking algorithms fail and so dispersion analysis is only possible by visual inspection. Such situations can occur in highly heterogeneous regions with complex surface-wave dispersion or where surface-wave arrivals are poorly emerged (as can often be the case with ambient-noise-derived Green’s functions from temporary seismic deployments). In these datasets, the poor signal-to-noise ratio, spectral holes, or limited bandwidth may therefore mean that manual analysis is the only choice. However, without an efficient workflow the feasibility of this can be seriously constrained by the analysis time for the potentially vast number of traces to be analyzed. We tackled this problem by implementing well-known techniques of dispersion curve analysis (traditional frequency–time analysis) in a fast and interactive graphical environment. It is specifically developed for high user processing speed, prioritizing fast computation, and high display responsiveness. This solution retains the benefits of manual dispersion picking for complex datasets, while maintaining good user processing efficiency. An experienced analyst can measure upward of 200 traces per hour. xdcpick stands for an X-window-based picking of dispersion curves.