Ali Osman Öncel and Ömer Alptekin

Istanbul University, Department of Geophysical Engineering,34850 Avcilar, Istanbul-Turkey.

In this study, the spatial complexity of fault populations along the strike-slip faults in Turkey are investigated by using the fractal (capacity) dimension. In the examination of spatial characters of strike-slip fault zones, the capacity dimension is obtained for The North Anatolian Fault Zone (NAFZ), The East Anatolian Fault Zone (EAFZ), and The North East Anatolian Fault Zone (NEAFZ) from the Active Fault Map of Turkey, by using box counting method. These are seismically active strike-slip fault zones transcending the Anatolian plate in E-W and N-S directions. The capacity dimension for these fault zones varies between 0.9>D₀>1.6, depending on the degree of complexity of the fault zone. High values of fractal (capacity) dimensions are related to zones with dense patterns of faults of different strike and high degree of fracturing or more intense deformations. Low values of fractal (capacity) dimension are related to regions with a predominant linear fault zone or, to regions where branching faults along the main fault are absent or undetermined. The highest value of D₀ (1.53) is observed near to Karlìova triple junction of the NAFZ with the EAFZ. This area is intensely deformed due to northward motion of the Arabian plate. Fractal dimension D₀ decrease along the NAFZ toward the Marmara region in the west where the NAFZ possibly breaks into three strands.