Fig. 4: Regular slow slip.
From: Spontaneous complexity in the dynamics of slow laboratory earthquakes
a The evolution of friction and average luminosity across three slow slip cycles, with b close-up of the third event. Note that luminosity increases during the entire 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 = 360 s. Dashed regions show locations of the stress rate calculations for panels (e) and (f). Arrows: black arrow, start of the instability; white, change of main rupture direction. Yellow circle: nucleation site. Video version of panels d–f in Supplementary Movies SM3 and 4.
