Recognition of fault causes in 9th March 2008 earthquake AryaShahr area by aftershocks analysis

Subject Areas :

حسام Yazdan panah ¹ , M.M KHatib ² , S.S Ahmadi zadeh ³

1 - دانشجوی کارشناسی ارشد تکتونیک، دانشگاه بیرجند
2 - عضو هیئت علمی دانشگاه بیرجند، گروه زمین شناسی
3 - عضو هیئت علمی دانشگاه بیرجند، گروه مهندسی محیط زیست

Received: 2016-09-06 Accepted : 2016-09-06 Published : 2009-09-23

Keywords: Aryan-Shahr, Aftershock, Sedeh fault, Gheysar fault,

Abstract :

In 9 March 2008 an earthquake with ML=5.1 ouccered in the west of Aryan-Shahr city, southeast ofIran. Many villages destroyed by this earthquake. Primarily, the Sedeh fault with N76 trend wasnominated as source of this earthquake. But the distribution of aftershock dispersals has been occurredin an ellipsoid district which is not superimposed on Sedeh Fault. The long axis of distributionellipsoid of aftershocks (N120) is nearly perpendicular to the Sedeh Fault trend. The seismic network,installed by Institute of Geophysics (university of Tehran), recorded more than 100 aftershocks during3 monthes. All data of 3 stations were processed, common aftershocks were separate, their parameterswere determine and were drawn on fault map.Therefore distribution of aftershocks location and main shock geometry of causing fault is known.Based on investigation of aftershock epicenter dispersal and the interpretation of aeromagnetic datareveal the presence a blind fault (Ghesar fault) parallel to long axis of distribution ellipsoid ofaftershocks.