Field Evidence for Southeast Black Sea Fault of Quaternary Age and Its Tectonic Implications, Eastern Pontides, Turkey

The Eastern Pontides, which is the under transpressional deformation zone, is an active mountain belt in northern Turkey that has been uplifting at a rate of more than 0.5 mm/year, along with push-up geometry. This uplift is accommodated by the dip/oblique slip normal fault segments of an en-echelon geometry mountain front mapped here for the first time. According to our geological mapping studies, the Southeast Black Sea Fault zone is about 65 km total long and more than 1 km wide and comprises nine fault segments. In the kinematic analysis conducted along the fault zone, fault planes have dip angles between 60o-90o to the north. The measured fault planes have rake angles range from 32o to 90o. Our findings indicate that (i) the faulting observed in the mountain front of the Eastern Pontides, the crustal thickness has increased due to thrust component strike-slip faults formed in a compressive regime where σ1 was horizontal at the initially, as a result of this, σ1 which is the horizontal position went into a vertical position, and lastly the former weakness zones were re-activated as normal faults, (ii) this weakness is defined as an Southeast Black Sea Fault that produces earthquakes have resulted in surface rupture in the Quaternary and therefore this fault should be considered in the class of “Quaternary Fault” in Turkey’s active fault maps.The Eastern Pontides, which is the under transpressional deformation zone, is an active mountain belt in northern Turkey that has been uplifting at a rate of more than 0.5 mm/year, along with push-up geometry. This uplift is accommodated by the dip/oblique slip normal fault segments of an en-echelon geometry mountain front mapped here for the first time. According to our geological mapping studies, the Southeast Black Sea Fault zone is about 65 km total long and more than 1 km wide and comprises nine fault segments. In the kinematic analysis conducted along the fault zone, fault planes have dip angles between 60o-90o to the north. The measured fault planes have rake angles range from 32o to 90o. Our findings indicate that (i) the faulting observed in the mountain front of the Eastern Pontides, the crustal thickness has increased due to thrust component strike-slip faults formed in a compressive regime where σ1 was horizontal at the initially, as a result of this, σ1 which is the horizontal position went into a vertical position, and lastly the former weakness zones were re-activated as normal faults, (ii) this weakness is defined as an Southeast Black Sea Fault that produces earthquakes have resulted in surface