Siesmotectonics-Siesmicity Assesment Of NW Iran

Category Tectonic & Seismotectonic
Group GSI.IR
Location 21th symposium on geosciences
Holding Date 24 May 2008

Abstract:
      Iranian plateau as one of the seismic zones, is located in Alpine-Hymalian siesmic belt.The northwest part of Iran (studied area)like the whole parts of it, is affected by convergence of Arabian shield and Eorasia plate.There are three major active faults in NW Iran which are :1)Tabriz fault 2)Uroomieh fault, and 3)Astara(Talesh) fault zone respectively .In this article we have presented time distribution of ancient earthquakes, epicenters of recent destructive earthquakes and their relationships with major active faults.Then we have calculated the reoccurrance period of destructive earthquakes(m=5) by statistical way as (95-145 ?5) years and seismic parameters of studied area by using Gotenberg-Rishter method .This assesment shows that destructive earthquakes in NW Iran have no long reoccurrance period and moderate magnitude.Therefore, highmagnitud earthquakes(M>7) in NWIran are unexpected. Finally modified seismotectonical map of the area is presented.

   General:
     Iranian plateau as one of the seismic zones, is located in Alpine- Hymalian seismic belt. The northwest part of Iran (studied area)like the whole parts of it, is affected by convergence of Arabian shield and Eorasia plate. There are three major active faults in NW Iran which are: 1)Tabriz fault 2) Uroomieh fault, and 3) Astara (Talesh) fault zone respectively. In this article we have presented time distribution of ancient earthquakes, epicenters of recent destructive earthquakes and their relationships with major active faults. Then we have calculated the reoccurrence period of destructive earthquakes (m=5) by statistical way as (95-145?5) years and seismic parameters of studied area by using Cotenberg-Rishter method. This assessment shows that destructive earthquakes in NW Iran have no long reoccurrence period and moderate magnitude. Therefore, highmagnitud earthquakes (M>7) in NW Iran are unexpected. Finally modified seismotectonical map of the area is presented.

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