Overview of the collapse of the X-shaped coronal structure. Top: AIA 171 Å images covering the 90 min surrounding the collapse. Overlaid on the earliest image are the slices used to generate the time-distance plots shown in Fig. 2. Slices A and B are 67 arcsec and 96 arcsec long, respectively; the arrow denotes the reference direction for the time-distance plots. Middle: NRH 430 MHz images showing the Type I storm source at the times of the above images. Overlaid is the field of view of the AIA images. Bottom: GOES 1–12 keV and RHESSI 3–6 keV light curves, showing the flares that occurred during the collapse. An animation of the collapse in AIA 171 Å data is available online.