Writers : Hasanzadeh,Hamid
Refference : M.Sc.Thesis-Ferdowsi University, Mashhad
Publishing Year : 1381

Abstract :

Coulomb stress modeling based on calculation of slip nucleation threshold on fault planes using Coulomb failure criteria and the stress changes resulted from movement of blocks on both sides of a rupture. Results of this modeling include the interaction between earthquakes and distribution of aftershokes and are in a good accordance with earthquake probabilities and changes in seismicity rate.

In this present research, changes in Coulomb stress on the active faults, resulted from the major earthquakes of Qaenat area, 1968 Dasht-e-Bayaz (Ms=7.3) and 1997 Zirkuh (Ms=7.3) earthquakes are calculated.

Static stress changes cause by the Dasht-e-Bayaz earthquake on the ruptures associated with 1968 September 1 Ferdows (Ms=6.4), 1979 November 14 Korizan (Ms=6.6) and 1979 November 27 Kuly-Boniabad (Ms=7.1) earthquakes and 1997 Zirkuh earthquake epicenter had been stress rise and loading. These changes on the 1976 Vendik earthquake (Ms=6.5) rupture and southern part of Zirkuh earthquake rupture had been stress drop and unloading.

After the Zirkuh earthquake, Kheybar-kuh area's NNW-SSE right-lateral strike-slip faults and Avaz and Gazik N-S right-lateral strike-slip faults have gained stress rise. The E-W left-lateral strike-slip Dasht-e-Bayaz fault has loosed static stress . The active NNW-SSE Nowazd reverse fault has been associated with stress drop and unloading and central part of Geryan and Aghavil thrust faults located to the west of Abiz fault have gained stress rise and loading.