Plots for single 3-min time slices of the median velocity and standard deviation of velocities about the median versus azimuth direction, calculated from the range of velocities found from all cross-correlation functions with the baselines within each station pair re-calculated for each assumed azimuth direction, in the usual form, counting clockwise from north. (a) Time slice commencing 21:05:00 UT using cross-correlations calculated after applying a high-pass filter at 0.01 Hz. (b) Time slice commencing 21:15:00 UT using cross-correlations calculated after applying a high-pass filter at 0.07 Hz. Note that the same y-axis is used for both velocity and standard deviation.