In this paper, the Cibyra segment of the Fethiye-Burdur Fault Zone (FBFZ) is investigated using direct field evidence, which helps clarify the controversial behaviour of this zone. The remains of the ancient city of Cibyra which is located on the Cibyra Fault provide invaluable data in documenting traces of fault deformations and related palaeoearthquakes. Slickensides on fault planes, deflected stream beds and terraces, fault-parallel elongated ridges along the Cibyra Fault are the clearest surface evidence for left-lateral faulting. Archaeoseismological evidence in the ancient city is consistent with the geological and geomorphological observations along the fault. Based on detailed field observations, it can be concluded that the Cibyra Fault reactivated in AD 417 and probably after the 7th century AD, causing extensive damage in Cibyra. Based on geological and geomorphological field evidence, fault offsets and deformed archaeological relics, it can be suggested that the Cibyra Fault is an active left-lateral fault capable of producing earthquakes of considerable magnitude. Furthermore, as the trend of the Cibyra Fault is consistent with the FBFZ it is concluded that NNE-SSW-trending faults in southwestern Turkey are active and the motion on them is left lateral.

In this paper, the Cibyra segment of the Fethiye-Burdur Fault Zone (FBFZ) is investigated using direct field evidence, which helps clarify the controversial behaviour of this zone. The remains of the ancient city of Cibyra which is located on the Cibyra Fault provide invaluable data in documenting traces of fault deformations and related palaeoearthquakes. Slickensides on fault planes, deflected stream beds and terraces, fault-parallel elongated ridges along the Cibyra Fault are the clearest surface evidence for left-lateral faulting. Archaeoseismological evidence in the ancient city is consistent with the geological and geomorphological observations along the fault. Based on detailed field observations, it can be concluded that the Cibyra Fault reactivated in AD 417 and probably after the 7th century AD, causing extensive damage in Cibyra. Based on geological and geomorphological field evidence, fault offsets and deformed archaeological relics, it can be suggested that the Cibyra Fault is an active left-lateral fault capable of producing earthquakes of considerable magnitude. Furthermore, as the trend of the Cibyra Fault is consistent with the FBFZ it is concluded that NNE-SSW-trending faults in southwestern Turkey are active and the motion on them is left lateral.