Evidence for surface rupture of the 1939 Erzincan earthquake based on field data and paleoseismology on the Ezinepazarı Fault (North Anatolian Fault Zone, Central Anatolia)

Abstract

: The Ezinepazarı Fault (EPF) is an active segment that restricts the Niksar Basin in the central part of the North Anatolian Fault Zone and has been the source of the devastating Mw 8.0 earthquake in the last 100 years. Traces of the surface rupture of the EPF, which occurred in AD 1939, can still be observed in the field today as a right-lateral strike-slip character. While paleoseismological studies were mostly focused on the western part of the North Anatolian Fault Zone (NAFZ) in previous studies, the studies on the central and eastern parts of the NAFZ are rarely addressed. In this context, trench-based paleoseismology studies were carried out on the surface rupture traces in order to determine both historical/prehistoric earthquakes caused by the fault and the Quaternary period characteristics of the EPF. According to the data obtained, at least two historical earthquake activities have been detected besides the last 1939 earthquake on the EPF. Accordingly, the first and second events occurred in E1: 5871 ± 2300 BP and E2: 1651 ± 128 BP, respectively. When the determined data are compared with the historical earthquake catalogs, it is concluded that Event 2 (E2) can be correlated with the AD 343 Niksar earthquake; thus, the EPF has an irregular earthquake recurrence interval.