Title

Complex Seismic Anisotropy and Mantle Dynamics beneath Turkey

Abstract

Seismic anisotropy is an unambiguous property of the deep Earth that is often detected through shear wave splitting (SWS) and anisotropic receiver function (RF) techniques, which are then used to infer the lithospheric and asthenospheric deformational structure. The Anatolian plate and its associated Mediterranean, Eurasian, and Arabian plate boundaries represent the consequences of a variety of convergent and transform tectonic regimes; these boundaries are thus well-suited for studying seismic anisotropy related to subduction, orogenic, and strike-slip processes. We apply a joint SWS and RF analysis to identify the magnitude and orientation of deformation associated with lithosphere-asthenosphere coupling beneath the Anatolian plate system as well as intra-plate fossil fabrics resulting from ancient and ongoing collision. SWS analysis reveals the existence of complex anisotropic fabrics beneath the Anatolian region, where the upper-layer fast orientations are either parallel to strike-slip faults or orthogonal to reverse faults. Strongly oriented NE-SW lower-layer fast orientations suggest that they originate from slab-modulated flow in the mantle wedge overlying the northward-subducting African plate. The results of the RF analysis show that the fast orientations are spatially variable but are generally consistent with crustal fabrics developed mostly through intensive faulting and are possibly associated with sub-vertical lower crustal shear zones.

Department(s)

Mining and Nuclear Engineering

Comments

The data used in this study were obtained from two sources: (1) the NEMC and (2) the IRIS DMC. We thank Dr. Beck Biryol for a helpful discussion about the data. We are grateful to Fansheng Kong for assistance with the data processing in addition to Kelly Liu and Stephen Gao for helpful discussions and comments. Special thanks go to Ahmed Elsheikh and Bin Yang for a discussion about Figs. 11b and 13 . This study was supported by Benghazi University, Libya . Also, this study was partially supported by Mining Engineering Department, Missouri University of Science and Technology, Rolla, Missouri, USA. The original and corrected XKS waveforms and other related data from the NEMC stations can be freely accessed at http://web.mst.edu/∼aalmwb/Turkey_SWS_2017/all/meas.html , and the data from the IRIS DMC are publicly accessible. The local S-wave results can be found at http://web.mst.edu/∼aalmwb/S_wave/all/meas.html , and the crustal anisotropy results can be found at http://web.mst.edu/∼aalmwb/Turkey_Crust_Anis.

Keywords and Phrases

African plate; Arabian plate; Faulting; Lithosphere; Mantle; S-wave; Seismic anisotropy; Shear zone; Strike-slip fault; Tectonic setting; Wave splitting; Turkey; Dynamics of lithosphere and mantle; Planetary interiors; Receiver function; Shear wave splitting

International Standard Serial Number (ISSN)

0264-3707

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2017 Elsevier, All rights reserved.

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