Analysis of correlation of Neotectonic and seismicity in Bakharden-Quchan zone

Two fundamental goals are followed in this paper: 1- Active neotectonics of the Kopeh Dagh Mountains particularly in its central part that is called the Bakharden-Quchan Zone in NE Iran for special features of faulting and role of faults within this zone in the collision between Arabia-Eurasia plates. 2- Seismicity hazards of faulting to recognize the relationship between asperities and earthquakes through analyzing the correlation of fractal dimension and b-value parameters. The Kopeh Dagh Mountain is accommodating a large portion of northward motion of central Iran with respect to Eurasia, involving a major right- lateral strike-slip fault system in its central part (the Bakharden-Quchan Zone). This fault system corresponds to the northeastern boundary of the Arabia-Eurasia collision and can be considered to be a lithospheric scale tectonic feature. The Kopeh Dagh Mountain forms a linear intercontinental fold-thrust belt trending NW-SE between the stable Turan platform and central Iran (Afshar Harb, 1979; Hollingsworth et al., 2006; Shabanian et al., 2009; Shahidi et al., 2013).

This research uses both historical and instrumental seismicity data along with observations from Landsat 7 satellite imageries, topographic data (SRTM), field observations and mathematical fractal dimension (D) model plus integral mathematical functions to find a logical correlation between tectonic movements, asperities and earthquakes in different active zones.

There is an array of active right-lateral strike-slip faults in the central part of the Kopeh Dagh Mountain which obliquely cut the range and produce offsets of several Kilometers in the geological structures. These faults all end in thrusting and link to blind faults, revealed by the uplifts and incision of the Late Quaternary terraces. These faults have rotated around their vertical axes and can account for several Kilometers of the N-S shortening. They are responsible for major destructive earthquakes in both 19th and 20th centuries and represent important seismic hazards for populous regions of NE Iran. These faults also require several Kilometers along-strike extension that is taken up by the westward component of motion between south Caspian sea basin, Shahrood fault system and both Eurasia and central Iran (Hollingsworth et al., 2006; Shabanian et al., 2009; Bretis et al., 2012).

The Bakharden-Quchan faults have identifiable ends, where they turn into thrusting and link to blind faults. The fault changing mechanism to reverse has caused increase of stress, shortening by thrusting in their end bending. Structural relation faults between this zone and the Binaloud Mountain through Meshkan transfer zone which is the major motion engine of this zone to put it constantly under neotectonic stresses for convergence of Arabia-Eurasia plates since the last Alpine orogeny phase. Most of the seismic activities of this zone could provide us with precious data on crust tension distribution through microseismic and computing parameters of b-value, fractal dimension (D) and mapping of local stresses. In neotectonic active zone b.