Fig. 13

Slow fault slip identified before the 2011 Tohoku-oki earthquake. a Two migrations of seismicity detected by the matched filter method within 1 month preceding the Tohoku-oki earthquake (after Kato et al. (2012)). Repeaters in the seismicity (stars) suggest the involvement of slow fault slip. b Long term (1996–2011) slip rate accelerations estimated from GPS and repeaters (after Mavrommatis et al. (2015). Colored circles show the locations of repeater sequences that showed statistically significant monotonic trends in recurrence interval during the study period. Observed GPS accelerations shown as black arrows with 2σerror ellipses, predicted in green. c Examples of repeater activity for three sequences shown in b (after Mavrommatis et al. (2015). The black bars and circles show the magnitude and timing of events and colored lines show recurrence intervals from the preceding event