Evaluation of tectonic activity effect in the Sepidar anticline: insight from fractal analysis of driange pattern, fractures and earthquakes epicenter, Zagros simply folded belt, Fars

Sepidar anticline in southwest of the Zagros, located in a tectonically active area, is delineated by the Sepidar, Sabzpoushan, Khafr and other active faults. This anticline has lost its cover of soft Miocene and Pliocene sediment and is now developed solely in the Asmari resistant limestone. Fractal dimensions of drainage pattern, fractures and earthquake in the Sepidar anticline show different values which varied in the NW-SE direction. Based on these variations, the northwestern parts of the fold have more tectonic activity than the southeastern parts. The transition between these parts correlated with saddle in the fold crest, which has undergone less uplift than the surroundings parts of the fold. Asymmetric forked drainage pattern, sinuosity drainage, and dry valley in the Sepidar flanks are geomorphological evidences of lateral propagation of folds. These geomorphological evidences and Inverse Distance Weighting (IDW) maps of fractal variations demonstrate the Sepidar anticline as a sub-cylindrical fold resulted from linear linkage with a saddle at the location where the two initial folds linked.