تفكيك زمين ساختي گسل كوهبنان

Kuhbanan fault zone tectonic segmentation

Kuhbanan fault is located between Tabas and Yazd blocks in the south west margin of central Iran microplate , extending from northeast of kerman to east of Bafgh with 300 km length and NW-SE strike . The fault is one of the most seismic structural trend in region. The latest seismic activity of the fault occurred on the first of April, 2002 with MS = 4.3 over northeast Dehzo-seg- ment. Kuhbanan Earthquake fault consists of several segments. Movement in the south east and central segments has been dextral strike slip with a large reverse component, and in the north­west segment it has also been dextral strike slip with a large normal component during plio-qua- ternary. Recognition of geometric segments of the kuhbanan fault zone is important in veiw of earthquake occurrance, easier description of structures and studying of landforms and geomorphic Indices. The Kuhbanan fault can be divided into fourty individual segments on the basis of tectonic map, fault geometry trace, variation in fault strike, rake angle, movement direction and subsidiary cross fault attributes along the fault zone. The movement on each segment is independent of neigh­bouring segments. The commonly observed boundary are located where (1) front bedrock or salients extend into the adjacent alluvial plain, (2) en echelon step in the range-bounding faults, (3) range-front fault are intersected by cross faults which trends at a high angle to the range front, and (4) fault bends. Conservative barriers with a relatively narrow deformation zone is formed in Tikdar, Jallalabad, Khan-Makan, Babkham, Charmis, Bidan pan, SE of Bonestan, Gibigon and Hossianabad. Nonconservative barriers with subsidiary reverse, thrust and normal faulting, volume changes, distributed crush and implosion breccias is formed in Khanok, Rigabad, Daho, Gazo, Sarbagh, Gisk, Dartangal, Dehzo, Rashk, Toghroljard, Abassabad, Godgaz, SE gavar, Kuhbanan, Darhod, SE Babroyh. Gazgar, Khoshabad, Kuh-e-sorkh and Kuh-e-segoush. From the geometry en ech­elon pattern with right stepover, and dextral strike slip movements of the Kuhbanan fault seg­ment, it is concluded that the most commonly observed barriers are transtensional. Barriers such as khanok, SE Dahzo, Gazo, Sarbagh, Gisk, Dehanager, SE Dehzo, NW Dehzo, Rashk, East Aliabad and Kuh-e-sorkh are transtens, ioinal and unpinned with releasing offset. Barriers such as Rigabad, Bonestan, Sarbagh, Dahzo, Khan-Makan, Toghroljard, Darhad, SE Bonestan are transpersional and pinned with restraining offset. East Jallaabad and Babkham barriers are transtensional and unpinned Bent.