ACTIVE TECTONIC ANALYSIS OF AVAJ-ABEGARM AREA (NW IRAN)

The study area is situated in southern boundary of central Alborz. NW trending fault segments characterize tectonic framework in Avaj-Abegarm fault zone. Compressional stress affecting the range is due to Arabian plate movement towards Iranian Plateau. Major NW trending structures in this district are formed by this stress. Fault planes in this extent mostly involve reverse left-lateral strike-slip movements. Changoureh-Avaj earthquake (Mw 6.4) occurred on June 22, 2002 in southern Qazvin. Avaj earthquake is the most destructive recorded seismic event in this area after Buin Zahra earthquake (Mw 7.0) in 1962. Accurate mapping on satellite images complemented by field investigations simplified fault offset determination. Major fault segments were mapped in order to recognize regional structural and geomorphic features. Avaj, Karafs, Abegarm, Abdarreh and Razan faults are major faults in this zone. Geomorphic documents for left-lateral strike-slip offsets affecting Quaternary alluvial fans range from ~180m to ~250m. There are similarly several sites including displaced qanats for ~10m to ~12m. Geomorphic, seismic and structural data confirm active tectonic processes in this zone. Future severe seismic events is probable in this region.

کلیدواژه ها:

Avaj ، earthquake ، fault ، seismic ، Abegarm