Plio-Quaternary Stress State in the Burdur Basin, SW-Turkey

Abstract

This study defines the Plio-Quaternary to present day stress regime in the Burdur Basin, located at the northeastern end of the Fethiye–Burdur Fault Zone in SW Turkey. This fault length, which is considered the landward continuation of the Pliny-Strabo trench, is an important feature in SW Turkey. The inversion slip vectors measured on fault planes indicate a consistent normal faulting stress regime during Plio-Quaternary time, continuing into recent times as indicated by earthquake focal mechanism inversions. Both states have consistent NW–SE trending horizontal minimum stress axes (σ3). The orientation of fault sets is predominantly around the NE–SW direction in the major Fethiye–Burdur Fault Zone, making the extension NW–SE. The mean stress ratio is 0.74 indicating a triaxial stress state, which is clearly different from radial extension. The NW–SE extension is probably responsible for the formation of the Burdur Basin during Plio-Quaternary time. This extension, which is probably caused by slab-pull force due to the subduction process along the Cyprus arc, produces a dominant normal motion along the FBFZ.