The study area is situated in the easternmost segment of the North Anatolian Fault System (NAFS), including the Karlıova triple junction (KTJ) where the NAFS intersects the East Anatolian Fault System (EAFS). The regional angular unconformity between intensely deformed pre-Quaternary rocks and the overlying undeformed neotectonic deposits clearly indicates that the onset of the strike-slip neotectonic regime and the formation of the related structures, namely the NAFS and EAFS, occurred in the early Quaternary (2.588 Myr). The present study focuses on the long-term (241-year) Tanyeri–Yedisu seismic gap, the onset age of the strike-slip neotectonic regime, and several key parameters of the Erzincan–Varto section of the NAFS. These are total dextral displacement, average slip rate, and the return period of the peak earthquake expected from the Tanyeri–Yedisu seismic gap. New field data, obtained from the detailed field geological mapping of the region, using the displacement of the Inner Tauride Suture as a structural marker and the Yedisu River as a geographic marker, clearly show that the total dextral displacement is 57 km. This offset was accumulated over an approximately a 2.6 Myr time interval. These values correspond to an average slip rate of 22 mm/yr and a return period of 205 ± 50 years for the peak earthquake originating from the Tanyeri–Yedisu seismic gap.