Fig. 3

Fault zone development as indicated by AE events. a Applied differential stress and the cumulative number of AE events plotted as a function of time. b–j The vertical cross section of the rock specimen showing AE event locations in nine time windows: b 12,500–13,720 s, c 13,720–13,740 s, d 12,500–13,000 s, e 13,000–13,500 s, f 13,500–13,720 s, g 12,600–12,700 s, h 12,700–12,800 s, i 12,800–12,900 s, and j 12,900–13,000 s