Seismogenic faulting of the sedimentary sequence and laterally variable material properties in the Zagros Mountains (Iran) revealed by the August 2014 Murmuri (E. Dehloran) earthquake sequence

Copley, Alex and Karasozen, Ezgi and Oveisi, Behnam and Elliott, John R. and Samsonov, Sergey and Nissen, Edwin (2015) Seismogenic faulting of the sedimentary sequence and laterally variable material properties in the Zagros Mountains (Iran) revealed by the August 2014 Murmuri (E. Dehloran) earthquake sequence. Geophysical Journal International, 203 (2). pp. 1436-1459. ISSN ISSN: 0956-540X, ESSN: 1365-246X DOI https://doi.org/10.1093/gji/ggv365

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Abstract

We present source models for the August 2014 Murmuri (Dehloran) earthquake sequence in the Zagros Mountains of Iran. An Mw6.2 mainshock was followed by an aftershock sequence containing five events of Mw ≥ 5.4. Models of P and SH waveforms show that all events had dominantly thrust-faulting mechanisms, and had centroid depths that place them within the thick sedimentary sequence, above the crystalline basement. The combination of our estimated focal mechanisms, relative relocations of the event hypocentres and the surface displacement patterns observed using InSAR imply that the mainshock and largest aftershock ruptured different fault planes and both contributed to the surface deformation. The fault planes both slipped in horizontally elongated patches, possibly due to rheological layering limiting the updip and downdip extent of rupture. The slip vector of the Murmuri mainshock implies that the decollement beneath the Lorestan Arc is weaker than any such feature beneath the Dezful Embayment, providing an explanation for the plan-view sinuosity of the range-front of the Zagros Mountains.

Item Type:	Article
Uncontrolled Keywords:	2015AREP; IA70
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access
Journal or Publication Title:	Geophysical Journal International
Volume:	203
Page Range:	pp. 1436-1459
Identification Number:	https://doi.org/10.1093/gji/ggv365
Depositing User:	Sarah Humbert
Date Deposited:	28 Apr 2016 12:52
Last Modified:	28 Apr 2016 12:52
URI:	http://eprints.esc.cam.ac.uk/id/eprint/3638

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