Fig. 6: Irregular slow slip.
From: Spontaneous complexity in the dynamics of slow laboratory earthquakes
a The evolution of friction and average luminosity across three irregular slow slip cycles, with b close-up of the third event. Note that luminosity increases only during the first part of the friction drop. c Qualitative stress change (inverse of luminosity change) along the shear direction with time, with d close-up of the third event. e, f Qualitative stressing rate (inverse of luminosity change rate, dL/dt with dt = 20 ms) in the shear (e) and horizontal (f) directions. g Snapshot of the luminosity at t = 130 s. Dashed regions show locations of the stress rate calculations for panels (e) and (f). Arrows: black, start of the third instability; white, the rupture reaches the topmost stressed microlithon; orange, second part of the friction drop not matched by changes in luminosity. Yellow circle: nucleation site. Video version of panels (d–f) in Supplementary Movies SM5 and 6.
