Estimation of the active Uplift rate using “precise leveling” in the Central Alborz Mountains, Northern Iran

The Alborz Mountains in northern Iran is an active fold and thrust belt which extended from Caucasus Mountains in the west to Binalud and north Afghanestan Ranges in the East. Active faults related uplift have not been systematically investigated across the Alborz Mountains. Here, we use the precise leveling technique to analysis active uplift and subsidence related to major controlling faults across the central Alborz Mountains. Our data gathered through a line that is perpendicularly aligned to the central Alborz Mountains along the N-trending Karaj-Chalus road. The results represent that the major active uplift of the southern part of the central Alborz Mountains has been focused in the hangingwall of the North Tehran and Mosha Faults with the uplift rate of 17±0.6 mm/22Yrs and 18.1 ± 0.6 mm/22Yrs respectively. The very low value of active uplift just at the vicinity of fault zones represent their present day locking behavior and reflect their higher potential of earthquake occurrence in the south central Alborz Mountains. There is also abnormal anomalies of 118 mm/22Yrs subsidence recorded in the footwall of Kandevan Fault. We attributed this high amount of subsidence to karstic related depressions developed in Upper Eocene evaporates in the fault footwall. Regional comparison of the mean active uplift rate shows relatively higher amount of uplift in the southern flank of the central Alborz Mountains (10.4 ± 0.6 mm/Yrs.) with respect to its northern flank (6.3 ± 0.6 mm/Yrs.).