28 March 1970 Gediz earthquake fault, western Turkey: Palaeoseismology and tectonic significance

On 28 March 1970, an unexpected and destructive earthquake (Ms = 7.2) originated along the Erdoǧmuş fault (EF), which forms the southern margin of the modern Erdoǧmuş-Yenigediz graben in the central part of the Akşehir-Simav fault system. The EF is a N-dipping normal fault, ∼12 km long, generally E-W-trending, and characterized by a minor right-lateral strike-slip component. To determine its past activity, a palaeoseismological exploratory trenching study was conducted. Two trenches (EFT-1 and EFT-2) were excavated on the ground surface rupture of the 1970 Gediz earthquake near Erdoǧmuş village. Based on the relative displacement between units observed and mapped in EFT-1, at least three events were identified. Two events were also identified in EFT-2. Only one of the events in EFT-1 can be dated via ¹⁴C. The estimated recurrence interval on the EF is ∼910 ± 40 years.