As in Fig. 5, but showing the total nonthermal footpoint areas A_nth,tot (left column) and the footpoint separation d_FP (right column) as a function of peak GOES soft X-ray flux I_SXR. The upper row shows A_nth,tot and d_FP at the time of the GOES SXR peak, while the lower row depicts the mean values of the volumes, with the error bars showing the whole range from minimum to maximum. For A_nth,tot, we additionally show power-law fits obtained with the WLS method (gray dotted line).