Preliminary Results of Long Term Strength of Lithosphere in the Zagros Mountains of Iran: Insight from Mechanical Modeling

A thre e-dimensi on al lithosphere model with hori zonta l dimensions of 1500 km x600 km and a depth ex tent of 70 km fo r the zagros is const ru ctedfrom available ge ophys ica l data to find out streng th of th e ou termost layers in thi s area . the structura l bou nda rie s of th e model a re based on th eresults from the deep se ismic sounding profiles . first th e finite element model for the temperature is so lved in order to obtain in iti al temperatureand the geot herm, aft er that st ructura l v iscoe las t ic problem is solved usin g th e same mes h as in the therm al init ia l co nd ition. pr eliminary re su ltsfo r wet and dry rheo logy indicate that th e dept h of the bdt is about 8 km and ii km for hot geo the rm and 10.5 km to14 km fo r co ld ge othe rm. there sults ar e in good ag ree me nt with foc al depth in the zagros tha t most ear thquakes occur in 8 to 15 km dep th (tat ar et ai. , 2004 and jackson et a i.,2008), that the lo ng- te rm str ength of the continental li thosph ere re s ided on ly in its up per pa rt , which wa s contained who lly within the cru st