Late Pleistocene, Holocene, and decadal constancy of slip-rate of the Doruneh strike-slip fault, Iran.

Wednesday, 17 December 2014: 10:35 AM
Richard T Walker1, Morteza Fattahi1, Zahra Mousavi2, Erwan Pathier3, Robert Alastair Sloan1, Morteza Talebian1, Alexander Llewellyn Thomas4 and Andrea Walpersdorf5, (1)University of Oxford, Oxford, United Kingdom, (2)université Joseph Fourier, Grenoble, France, (3)University Joseph Fourier Grenoble, Grenoble Cedex 9, France, (4)University of Edinburgh, Edinburgh, United Kingdom, (5)ISTerre Institute of Earth Sciences, Saint Martin d'Hères, France
The Doruneh left-lateral strike-slip fault of NE Iran has a prominent expression in the landscape, showing that the fault is active in the late Quaternary. Existing estimates of its slip-rate vary, however, which has led to suggestions that it may exhibit temporal changes in activity. Using high-resolution optical satellite imagery we make reconstructions of displacement across four alluvial fans that cross the Doruneh fault, and determine the ages of these fans using luminescence dating, combined with U-series dating of pedogenic carbonates in one case. The four fans, which vary in age from 10-100 kyr, yield estimates of slip rate of ~2-3 mm/yr. We compare the average slip-rate measurements to the rate of accumulation of strain across the Doruneh fault using GPS and InSAR measurements, and find that the slip-rate is likely to have remained constant - within the uncertainty of our measurements - over the last ~100 ka. The slip-rate that we measure is consistent with the E-W left-lateral Doruneh fault accommodating N-S right-lateral faulting by 'bookshelf' faulting, with clockwise rotation about a vertical axis, in a similar manner to the Eastern California Shear Zone.