Surface rupture history and 18-ka-long slip rate along the Pazarcık segment of the East Anatolian Fault

Abstract

We investigate the paleo earthquakes and slip-rate on the Pazarcık segment of East Anatolian Fault which has involved surface rupture of 6 February 2023 Pazarcık-Kahramanmaraş earthquake (Mw:7.7) and provided insights of the long-term behavior of this major continental fault. Paleoseismologic data from two trench sites, reveal evidence for at least five surface ruptures in the Holocene Period. The historical earthquake of 1114AD is verified at both trench sites but the following event of 1513AD is only identified at one site. In addition, the age difference of the older events shows historical activity are separated by much longer periods of relative quiescence that range from 500 years to 1000 years which suggest quasiperiodic earthquake occurrence on sub-segments of the Pazarcık segment. Our fault parallel trenches revealed 101±5 m offset in the last 18 ka and 51±1 m offset in the last 9 ka on a buried stream channel and the actual channel of the same stream respectively. The correlation of the maximum and abandonment age of the channel with measured offsets revealed 5.6 mm a -1 long-term slip rate of the fault. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6850786