Block modeling of present-day deformation of Anatolia and slip rates along the North Anatolian Fault

I use GPS velocity field and published geologic slip rates to constrain an elastic block model for Anatolia and surrounding regions. The elastic block model allows us to define plate motion and both strike and tensile slip rates along the major faults. Previous studies (eg., McClusky et al., 2000; Reilinger et al., 2006) have pointed to the discrepancy between geodetic-derived slip rate estimates of around 25 mm/yr on the North Anatolian Fault (NAF) and geologically-derived slip rate estimates of roughly 18 mm/yr. To address this discrepancy, I conduct two inversions; a geodetic-only inversion and a joint inversion. While I constrain one model with only geodetic data, I constrain the other model with both geodetic data and geologic slip rates. On the basis of the GPS velocity field, the Anatolia and Aegean blocks show counterclockwise motion with respect to the Eurasian plate, and the rate of this motion is increasing towards to the Hellenic arc. The geodetic-only inversion gives higher slip rate and deeper locking depth estimates for the North Anatolian Fault than joint inversion. The geodetic-only inversion gives a North Anatolian Fault (NAF) slip rate of approximately 26-27 mm/yr with locking depths of 20-25 km (preferably 23 km). The joint inversion gives a NAF slip rate of approximately 18-19 mm/yr with a shallower locking depths of 12-16 km (preferably 14 km). The geodetic-only inversion fits the GPS data better than the joint inversion with a normalized chi-square of 2.8-2.9 compared to the joint inversion normalized chi-square value of 3.1-3.2. However, the slip rates in the joint inversion are consistent with the geologic slip rates and the locking depths of 12-16 km are consistent with the depth of background seismicity, suggesting this result is consistent with more observational constraints than the geodetic-only inversion.