Paleoseismological investigations on a slow-moving active fault in central Anatolia, Tecer Fault, Sivas

Tecer Fault is a N60˚-70˚E-trending, left-lateral, strike-slip fault to the south of the town of Sivas, Turkey. This fault is considered as the east-ward continuation of Deliler Fault, which was classified as a probably active, left-lateral fault on the Active Fault Map of Turkey. We investi-gated the field characteristics and paleoseismic history of Tecer Fault in detail. After analyzing aerial photographs and satellite images, we mapped the exact fault trace on a 1/25,000 scale topographic map, be-tween the towns of Deliilyas in southwest and Bogazdere in northeast. Tecer Fault is characterized by morphological features such as offset streams and gullies, linear depressions and scarps, and elongated hills. Four paleoseismological trenches were excavated on the northeastern ex-tent of the fault. Two past earthquakes were identified in these trenches, and the dates of the collected charcoal samples suggested that the first of these earthquakes occurred about 8000 B.C. while the more recent event took place around 3500 B.C. Field observations and paleoseismic data in-dicate that Tecer Fault is an active, pure sinistral, strike-slip fault, and that there is about a 4500 years time span between the two earthquakes. It is also clear that there has not been any surface-ruptured faulting over the last 800 years. Compared with the earthquake characteristics of other strike-slip fault zones in Turkey in terms of time-slip relations, the slip rate can be estimated as about 1 mm/yr on Tecer Fault. 1