EGU24-8282, updated on 08 Mar 2024
https://doi.org/10.5194/egusphere-egu24-8282
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

A twisted ribbon of subducted lithosphere beneath southeast Anatolia and its seismotectonic implications

Sonia Yeung1, Gordon Lister2, Wim Spakman3, Oğuz Göğüş4, Marnie Forster1,5, Adam Simmons6, and Hielke Jelsma7
Sonia Yeung et al.
  • 1Structural and Tectonics, Research School of Earth Sciences, The Australian National University, 142 Mills Road, ACTON, 2601, Canberra Australia
  • 2W.H. Bryan Mining and Geology Research Centre, Sustainable Minerals Institute, The University of Queensland, Brisbane 4068, Australia
  • 3Department of Earth Sciences, Utrecht University, 3584 CB, Utrecht, The Netherlands
  • 4Istanbul Technical University (ITU), Eurasia Institute of Earth Sciences Türkiye
  • 5ANU Argon Geochronology Facility, Research School of Earth Sciences, The Australian National University, 142 Mills Road, ACTON, 2601, Canberra Australia
  • 6Anglo American Plc, 17 Charterhouse Street, London, EC1N 6RA, United Kingdom
  • 7Anglo American Plc, 144 Oxford Street, Johannesburg, 2196, South Africa

Forensic analysis of the geological architecture in the aftermath of destructive earthquakes is an essential step to identify controlling structures that need to be monitored. Here we suggest the sequence of events during the February 2023 Turkey–Syria earthquakes was driven by the roll back of a twisted ribbon of subducted lithosphere beneath southeast Anatolia. We assume that the February 2023 Turkey–Syria earthquakes were short-term manifestations of a longer-term tectonic process. To investigate, we built a three-dimensional (3D) mesh frame defining the geometry of subducted Tethyan lithosphere in the Eastern Mediterranean, using the UU-P07 global tomography model, and where appropriate, earthquake hypocentre sets from the Global Centroid Moment Tensor project (GCMT) and from the International Seismic Centre (ISC). The 3D model of the subducted Tethyan lithosphere exhibits three variably twisted ribbons. The Cyprus ribbon is subducted to ~280 km depth and is ~120 km wide, and it twists and curls parallel to its length by ~20 degrees anticlockwise.

The geometry prior to subduction can be estimated by floating the mesh back to the surface using the Pplates program. The process of subduction can be visualised by incorporating the floated mesh into a 2D+time tectonic reconstruction from 125 Ma to the present. This leads to the inference that the ribbons are associated with slab tearing during roll back of the Tethyan lithosphere, due to the accretion of the Lycian block and the Cyprus promontory. The twisting motions can be related to a lateral push sideways caused by anticlockwise vertical axis rotation of the Arabia indenter during opening of the Red Sea rift and the Gulf of Aden. We suggest that the Anatolian lithosphere is being stretched by ongoing differential roll back caused by drag of the Cyprus ribbon through the asthenosphere underlying southeast Anatolia. This motion continually triggers failure along strike-slip faults while facilitating the continued indentation of Arabia. Seismotectonic analysis of aftershock sequences highlights the underlying geodynamics.

How to cite: Yeung, S., Lister, G., Spakman, W., Göğüş, O., Forster, M., Simmons, A., and Jelsma, H.: A twisted ribbon of subducted lithosphere beneath southeast Anatolia and its seismotectonic implications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8282, https://doi.org/10.5194/egusphere-egu24-8282, 2024.