a, b Snapshots of the rupture expansion history every two seconds. Colours shading indicates the fault slip rate average over 2 s intervals. The black dashed contour presents the pseudo-rupture front with a rupture velocity of 2.0 km/s. F1, F2, F3 correspond to the faults in Fig. 3. c Presents slip rate at the six locations in a. Time is relative to the hypocentral origin.