Evidence of extensional and strike-slip deformation in the offshore Gökova-Kos area affected by the July 2017 Mw6.6 Bodrum-Kos earthquake, eastern Aegean Sea

  • Neslihan Ocakoğlu
  • Paraskevi Nomikou
  • Yeliz İşcan
  • Maria Filomena Loreto
  • Danai Lampridou
Original

Abstract

The interpretation of new multichannel seismic profiles and previously published high-resolution swath and seismic reflection data from the Gökova Gulf and southeast of Kos Island in the eastern Aegean Sea revealed new morphotectonic features related to the July 20, 2017 Mw6.6 Bodrum-Kos earthquake offshore between Kos Island and the Bodrum Peninsula. The seafloor morphology in the northern part of the gulf is characterized by south-dipping E–W-oriented listric normal faults. These faults bend to a ENE–WSW direction towards Kos Island, and then extend parallel to the southern coastline. A left-lateral SW–NE strike-slip fault zone is mapped with segments crossing the Gökova Gulf from its northern part to south of Kos Island. This fault zone intersects and displaces the deep basins in the gulf. The basins are thus interpreted as the youngest deformed features in the study area. The strike-slip faults also produce E–W-oriented ridges between the basin segments, and the ridge-related vertical faults are interpreted as reverse faults. This offshore study reveals that the normal and strike-slip faults are well correlated with the focal mechanism solutions of the recent earthquake and general seismicity of the Gökova Gulf. Although the complex morphotectonic features could suggest that the area is under a transtensional regime, kinematic elements normally associated with a transtensional system are missing. At present, the Gökova Gulf is experiencing strike-slip motion with dominant extensional deformation, rather than transtensional deformation.

Notes

Acknowledgements

This work combines two different projects. (1) The GEOWARN project (contract no. IST-1999-12310): the European Commission is acknowledged for their financial contribution, and the officers and crew of R/V Aegaeo are gratefully acknowledged for their substantial contribution to the field work. (2) Istanbul University Graduate Studies Research Funds (project no. 3347): the officers and crew as well as the scientists and technicians onboard the TCG Çubuklu and TCG Mesaha-II of the Turkish Navy, Department of Navigation, Hydrography and Oceanography are gratefully acknowledged for providing bathymetry data for the Gökova Gulf. The manuscript benefitted from constructive comments by two anonymous referees as well as the journal editors.

Compliance with ethical standards

Conflict of interest

The authors declare that there is no conflict of interest with third parties.

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Authors and Affiliations

  1. 1.Department of Geophysical Engineering, Faculty of MinesIstanbul Technical UniversityIstanbulTurkey
  2. 2.Department of Geology and GeoenvironmentNational and Kapodistrian University of AthensAthensGreece
  3. 3.Department of Geophysics, Faculty of EngineeringIstanbul UniversityIstanbulTurkey
  4. 4.Institute of Marine Sciences, CNRBolognaItaly

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