At the Balkar Trench T2, excavated in the northeastern part of the Pazarcık segment of the East Anatolian Fault, evidence for the oldest surface rupturing event is not preserved as discrete fault planes but is instead inferred from deformation of the stratigraphy. Yönlü and Karabacak (2023:4) note that, although no identifiable fault splays predating Event X were observed, deformation is expressed through tilting of sedimentary units. Specifically, southeast-dipping Units 11 and 12 show evidence of back-tilting against local topography, likely produced by coseismic deformation consisting of strike-slip motion with a reverse (compressional) component. This tilting created a topographic depression that promoted ponding, allowing the accumulation of organic-rich clay deposits in Units 13 and 14. These deposits were subsequently buried by colluvial deposits, preserving the record of this earlier deformation phase.

As no radiocarbon sample is available to date the deposition preceding this "oldest" event, its age can only be constrained by a terminus ante quem. This is provided by a charcoal sample from unit 13, which yielded a calibrated age of 2811–2411 BCE ( 2σ). Accordingly, the "oldest" event should have occurred prior to 2411 BCE.

Figure 4b - Trench Log of SW wall of Balkar trench - Thin black lines are stratigraphic contacts - colours show units - red lines are traces of faults - small rounded outlines are gravels - (trench location 374 154 m E/417 775 m N) - Yönlü and Karabacak (2023)