Time-distance maps (a and c) along slits L1.1 and L1.2 (Figs. 4a and 4b). The number of each slit is shown as a white circle in the bottom-right side. The intensity motions of interest are the events E₁ to E₄. The red crosses show the times of the intensity peaks associated with the events at different locations. The red line represents the computed PoS velocity on the time-distance map for each event. Panels (b) and (d) show four examples of light curves at distinct locations (noted P₁ to P₄) at the times of E₁ and E₄, respectively. The vertical dotted lines represent the time intervals that include the intensity peak. A Gaussian function (in blue) is fitted to estimate the central time of the intensity peak (see Appendix A for more details). The events E₁, E₂ and E₄ seem to appear almost instantaneously along the slit, within the limitations due to the HRIEUV temporal resolution. In that case, we only show the highest resolvable PoS velocity as a lower limit. The intensity values are in DN/s.