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Lithospheric structure beneath the Zagros collision zone resolved by non-linear teleseismic tomography

Shomali, Z. Hossein and Keshvari, Forough and Hassanzadeh, Jamshid and Mirzaei, Noorbakhsh (2011) Lithospheric structure beneath the Zagros collision zone resolved by non-linear teleseismic tomography. Geophysical Journal International, 187 (1). pp. 394-406. ISSN 0956-540X. https://resolver.caltech.edu/CaltechAUTHORS:20111017-112912641

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Abstract

The upper-mantle structure across the Zagros collision zone, in southwest Iran, is investigated using a non-linear weighted damped least-squares teleseismic tomography approach. The resolution of the structures/transitions in the upper mantle is enhanced significantly by correcting the teleseismic relative arrival time residuals for an a priori crustal velocity model and then performing the inversion with fixed crustal blocks. To investigate whether or not the lithospheric blocks and major transitions in the resulting model are required by the data or are artefacts of the inversion, the data were inverted using two different inverse methods (singular value decomposition and a quadratic programming method). New high-quality seismic velocity models show apparent correlation between surface geological features and seismic velocity structures at lithospheric depth across the Zagros collision zone. The image shows a sharp lithospheric boundary at the Main Zagros Thrust between 100 km and 250 km depth with P-wave velocity about 3 per cent faster within the Arabian Shield to the south. A step-like increase in lithospheric thickness across the Zagros collision zone is assumed to separate two different mantle structures namely the Arabian (to the south) and the Eurasian (to the north) domains. The most striking feature resolved is a north-dipping slab-like positive velocity anomaly.


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http://dx.doi.org/10.1111/j.1365-246X.2011.05150.xDOIArticle
Additional Information:© 2011 The Authors. Geophysical Journal International © 2011 RAS. Accepted 2011 July 11. Received 2011 July 11; in original form 2010 April 6. Article first published online: 8 Aug. 2011. Seismological data used in this paper were retrieved from the data management centre of the French portable seismic instrument pool hosted by LGIT (Grenoble University-CNRS), http://bdsis.obs.ujfgrenoble.fr/. We thank C. Péquegnat and H. Pedersen (LGIT Grenoble) for their valuable help. Some figures were made using the Generic Mapping Tools (GMT) version 4.2.1 (Wessel & Smith 1998; www.soest.hawaii.edu/gmt, last accessed 2010 August). We would also like to thank the Associate Editor, Gabi Laske, and four anonymous reviewers for their constructive comments and useful suggestions. We also thank Roland Roberts (Department of Earth Sciences, Uppsala University, Sweden) and Faramarz Tutti (Department of Geology, University of Tehran, Iran) for their valuable comments on the manuscript.
Subject Keywords:Body waves; Seismic tomography; Continental tectonics: compressional
Issue or Number:1
Record Number:CaltechAUTHORS:20111017-112912641
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20111017-112912641
Official Citation:Shomali, Z. H., Keshvari, F., Hassanzadeh, J. and Mirzaei, N. (2011), Lithospheric structure beneath the Zagros collision zone resolved by non-linear teleseismic tomography. Geophysical Journal International, 187: 394–406. doi: 10.1111/j.1365-246X.2011.05150.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:27252
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:17 Oct 2011 22:19
Last Modified:03 Oct 2019 03:22

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