Palaeoseismicity of the Dinar fault, SW Turkey

The NW-SE-trending Dinar fault is an active normal fault upon which the 1 O ctober 1995 earthquake (M = 6.1) occurred. The 1995 earthquake resulted in a c. 10-km-long surface rupture with the south side down-thrown by less tha n or equal to 50 cm. Investigations of two trench sites perpendicular to th e 1995 rupture suggest at least two prior large earthquakes in historical t imes. Radiocarbon dates and historical records constrain the age of events between 1500 BC and AD 53, event 2 possibly coinciding with the earthquake that damaged Dinar (the ancient city of Apamea Kibotos) in c. 80 BC and eve nt 1 around 1500 BC. Surface displacements determined for events 1 and 2, c ompared to the 1995 surface faulting, indicate that M > 6.8 earthquakes wer e associated with each rupture. Using the total displacement in trenches, a slip rate of about 1 mm yr(-1) can be estimated for the Dinar fault. Obser vations suggest that the return period for large earthquakes in the Dinar a rea is about 1500-2000 years.