A 3000-year Record of Surface Rupturing Earthquakes at Gunalan; Variable Rupture Lengths on 1939 Erzincan Earthquake Rupture Segment of the North Anatolian Fault, Turkey

The North Anatolian Fault is a ~1200 km long right-lateral strike-slip fault that forms the
northern boundary of the Anatolian plate. A damaging sequence of earthquakes ruptured
almost the entire fault in the twentieth century. This study adds to the growing number of
paleoseismic investigations on the 350 km long 1939 Erzincan earthquake rupture
segment, which is toward the eastern end of the North Anatolian Fault in Turkey. Using
three paleoseismic trenches located along about 2km of the principal fault strand, this
study determines the timing of five earthquakes prior to the 1939 earthquake. The first
three earthquakes are correlated to historical earthquakes in A.D. 1668, 1254, 499 and
two further events were identified at 881 – 673 B.C. and 1406 – 1291 B.C. (2σ age
ranges). By comparing the earthquake timing determined in this study to the results of
other paleoseismic investigations on the 1939 rupture segment, it becomes clear that this
historical rupture segment does not always rupture in unison. This analysis indicates that
the A.D. 499 earthquake was the last time the 1939 rupture segment ruptured in unison;
although partial ruptures of the 1939 rupture segment occur more frequently and also
produce large magnitude earthquakes (> Mw 7).