Earthquake history of the Milas Fault: an active dextral fault in an extensional province (SW Anatolia, Türkiye)

The Milas Fault (MF) is a poorly understood active fault located between the Büyük Menderes graben to the north and the Gökova graben to the south within the Anatolian–Aegean Region, SW Türkiye. This dextral strike-slip fault has a length of 55 km between Bafa Lake in the northwest and Çamlıca village in the southeast, with a general strike of N60°W, and its surface trace displays two separate geometric segments. We mapped the geomorphological and geological features of the MF using Google Earth© images, digital elevation models (DEMs) and field observations. The surface traces and kinematic characteristics of the MF were defined by the slickenlines on the partly altered fault planes, morphological lineaments and offset streams, which all suggest a dominant horizontal deformation for this tectonic structure. Moreover, we excavated three palaeoseismological trenches to expose signs of palaeoearthquakes on the MF and to evaluate its seismic hazard potential. Evidence of three palaeoearthquake events was revealed in trenches according to the stratigraphic and structural relationships of the exposed strata. The modelled age limits for these earthquakes yielded 2913–2117 BC, 7680–7043 BC and before 8354 BC from youngest to oldest. Based on these findings, the MF has produced surface-rupturing earthquakes in the Holocene epoch. Although there are no constrained dates to propose a recurrence interval, combined data from field observations, morphology, seismic records and palaeoseismology indicate that the Milas Fault is an active structure and has the potential to produce an earthquake with a magnitude of Mw 6.6–7.1 in the future.