Modelling tectonic deformation along the North-Anatolian Fault in the Sea of Marmara

Type Article
Date 2020-11
Language English
Author(s) Bulkan S.1, Vannucchi P.2, Gasperini L.3, Polonia A.3, Cavozzi C.4
Affiliation(s) 1 : Earth Sciences Department, Royal Holloway, University of London, Egham, UK
2 : Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via La Pira, 4, Firenze, Italy
3 : Istituto di Scienze Marine-Consiglio Nazionale delle Ricerche (ISMAR), IT-40129 Bologna, Italy
4 : NEXT – Natural and Experimental Tectonics research group, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy
Source Tectonophysics (0040-1951) (Elsevier BV), 2020-11 , Vol. 794 , P. 228612 (13p.)
DOI 10.1016/j.tecto.2020.228612
Keyword(s) Analogue modelling, Pull-apart basins, Stress transfer, Fault orientation, Cinarcik basin, Sea of Marmara

Using analogue techniques, we attempted to model the complex tectonic deformation pattern observed along the North-Anatolian Fault in the Sea of Marmara from morpho-bathymetry and seismic reflection images. In particular this paper focuses on the so-called Cinarcik segment of the fault connecting the eastern Izmit segment, which entirely ruptured during the Mw 7.4, 1999 earthquake, to the western segment of the Central High. The Çınarcık segment, potentially loaded after the Izmit earthquake, is expected to rupture during an earthquake occurring in the near future, possibly the next decades, with a high potential to affect the Istanbul metropolitan area. Our analysis suggests that the development of the observed structures accommodating strike-slip, transtensional and transpressional deformations, could be explained by changes in the geometry of fault segments within a right-lateral strike-slip tectonic regime. Tectonic deformations were reproduced in the analogue model by imposing a small (about 10°) and sharp difference in the relative orientations of the strike-slip segments at the edges of a major releasing bend. In the model slower strain accumulation occurs along the analogue of the Çınarcık segment than along the analogue of the Izmit segment of the fault. This would predict a delay for earthquakes triggered by stress transfer between the Izmit and Çınarcık segments. The model further predicts that most of the deformation in the Çınarcık basin is controlled by the sharp changes in the geometry of the fault itself.

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