The 2012 August 11 Ahar earthquakes: consequences for tectonics and earthquake hazard in the Turkish–Iranian Plateau

Alex Copley (1) , Mohammad Faridi (2) , Manoucher Ghorashi (2) , James Hollingsworth (3) , James Jackson (4) , Hamid Nazari (2) , Behnam Oveisi (2) , Morteza Talebian (2)

1 BULLARD LABORATORIES,UNIVERSITY OF CAMBRIDGE - Bullard Laboratories, University of Cambridge, Madingley Road, Cambridge CB3 0EZ, UK
2 Geological Survey of Iran
3 GEOAZUR 7329 - Géoazur
4 Bullard Laboratories

We have examined the faulting in the 2012 August 11 Mw 6.4 and 6.3 Ahar (NW Iran) earthquakes using a combination of field mapping, remote-sensing observations of tectonic geomorphology, the cross-correlation of optical satellite images and the inversion of seismic waveforms. The first event was close to pure strike-slip, and the second was an oblique combination of thrust and strike-slip motion. Mapped surface ruptures indicate at least one of these events accommodated mostly right-lateral strike-slip motion on an ∼E–W striking plane. The occurrence of these earthquakes highlights the spatially distributed deformation in NW Iran, which has implications for both hazard assessment (the Ahar events killed over 300 people and injured over 3000), and also tectonic models of the region. Furthermore, these earthquakes demonstrate that the tectonics of the Ahar area is characterized by strike-slip faulting and a component of shortening, and not the previously suggested extension.

Domaines: Sciences de la Terre

Alex Copley, Mohammad Faridi, Manoucher Ghorashi, James Hollingsworth, James Jackson, et al.. The 2012 August 11 Ahar earthquakes: consequences for tectonics and earthquake hazard in the Turkish–Iranian Plateau. Geophysical Journal International, 2014, 196 (1), pp.15 - 21. ⟨10.1093/gji/ggt379⟩. ⟨hal-01854884⟩