The accommodation of Arabia-Eurasia plate convergence in Iran

Continental convergence between Arabia and Eurasia is taken up by distributed deformation in Iran. At wavelengths large compared with the thickness of the lithosphere this deformation is best described by a continuous velocity field. The only quantitative source of information on the spatial distribution of strain rates within Iran is the record of earthquakes. The style of deformation observed in the seismicity can be reproduced by simply minimizing the rate of work in a continuous viscous medium that has to accommodate the Arabia-Eurasia plate motion between the defined shapes of Iran's rigid borders. When, in addition, we specify central Iran, Azerbaijan, and the southern Caspian basin to be relatively rigid blocks within the deforming zone, then the fit to the style of the observed strain rate distribution is even better. The whole plate motion can be accommodated by a velocity field with the same orientations and relative magnitudes of principal strain rates seen in the earthquakes but with larger absolute magnitudes. -from Authors