RPWs observed across the MFR eruption. Panels a–c: power spectra of time series along Cut1 (black) and Cut2 (green) in the time-distance maps in panels d–f, which are constructed by applying the linear slit (Fig. 2d) to 1600, 304, and 171 Å images, respectively. The time-distance map in panel g is made by applying the circular slit (Fig. 4b) to 1600 Å images. The PROI is bounded by two red dashed lines in panels d and g.