عنوان مقاله [English]
The Garmsar Fault with a length of about 75 km and E-W trend is located in Garmsar.This Fault observed in north of Garmsar and eastern part of central Alborz with slop toward north, continus east of Eyvanakey Fault. Base of the morphotectonical investigation, along the Garmsar Fault this fault is devided to 5 segments from east (Dehnamak village) to the west (Eyvanakey), with attention to this segmentation we could consider the branch of kuh-e-sorkh Fault at west of Garmsar in kuh-e-sorkh anticline such as separated fault with slop toward north and pressure mechanism with small left-lateral strike slip component. Base on observations and Paleostress measurment along the Garmsar Fault in Bon-e-kuh station and eastern segment of this fault, we could consider that Paleostress direction around Neogen Time, is N-S with pressure component. However, base of data, is gain from morphotectonical investigations, young and overcome mechanism in eastern segment (Fault segment 1) left-lateral with pressure component, on the other side, in kuh-e-sorkh anticline at western part of research area, considered stress direction at quaternary period E-W under the effect of Thrust fault with left-lateral component. Base of this study from geometry point of view, the Garmsar Fault is a fault with slop toward north which is able to devide in to 5 segments that is strike and geometry of each fault segment mechanism is from left-lateral with pressure component until Tension and the Garmsar Fault is considered as an active fault in quaternary period. Maximum and minimum on the left horizontal displacement measured on the fault equal to 220 meters and 4 meters of a fault on the part of the fault system and third segment on the drainages of Garmsar displaced is visible.