Eastern Termination of the Subducting African Lithosphere Beneath Anatolia Imaged by Teleseismic P wave Tomography

2009-12-14
Biryol, C. Berk
Zandt, George
Beck, Susan L.
Özacar, Atilla Arda
Schmandt, Brandon
A variety of complex tectonic processes are active in Anatolia. Collision related plateau formation dominates the present lithospheric deformation toward the east and slab roll-back related back-arc extension takes place toward the west. The two zones are connected at the northern part of the region by strike-slip faulting along the right-lateral North Anatolian Fault. Recent seismological studies show that the Eastern Anatolian Plateau (EAP) is supported by hot asthenosphereric material that was emplaced beneath the plateau following the detachment of subducted Arabian lithosphere. The westward continuation of the deeper structure of Anatolia is less well constrained due to the lack of geophysical observations. In order to study how the deeper lithosphere and mantle structure evolves spatially from east to west, we used teleseismic P-wave tomography and data from several temporary and permanent seismic networks deployed in the region. A major part of the data comes from the North Anatolian Fault passive seismic experiment (NAF) that consists of 39 broadband seismic stations operated at the north central part of Anatolia between 2005 - 2008. We also used data collected from permanent seismic stations of the National Earthquake Monitoring Center (NEMC) and stations from the Eastern Turkey Seismic Experiment (ETSE). Approximately 15,000 P-wave travel time residuals, measured in multiple frequency bands, are inverted using approximate finite-frequency sensitivity kernels. Our tomographic model reveals a fast anomaly that corresponds to the subducted portion of the African lithosphere along the Cyprean Arc. This fast anomaly dips northward beneath central Anatolia with an angle of approximately 45 degrees. However, the anomaly disappears rather sharply east of 36 degree longitude. This eastern edge of the slab also marks the western boundary of the EAP and Arabia-Eurasia collision zone. Beneath EAP our model reveals distributed slow anomalies down to 400 km and upper mantle beneath central Anatolia is relatively faster in comparison to that of EAP. This indicates that the existence of subducted African lithosphere might be the major factor that controls the sharp transition of upper mantle structures from the central Anatolia to the EAP.
American Geophysical Union (AGU) 2009 Fall Meeting

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Citation Formats
C. B. Biryol, G. Zandt, S. L. Beck, A. A. Özacar, and B. Schmandt, “Eastern Termination of the Subducting African Lithosphere Beneath Anatolia Imaged by Teleseismic P wave Tomography,” San-Francisco, Kostarika, 2009, vol. 90, Accessed: 00, 2021. [Online]. Available: http://abstractsearch.agu.org/meetings/2009/FM/sections/T/sessions/T51C/abstracts/T51C-1537.html.