ICG2022-369, updated on 20 Jun 2022
10th International Conference on Geomorphology
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Quantifying active faulting using marine terraces, Kythera Island, Greece

Konstantinos Tsanakas1, Julius Jara-Muñoz2, Efthimios Karymbalis1, Cengiz Yildirim2,3, Kevin Pedoja4, Dimitrios-Vasileios Batzakis1, and Diamantina Griva1
Konstantinos Tsanakas et al.
  • 1Harokopio University of Athens, Department of Geography, Athens, Greece (ktsanakas@hua.gr, karymbalis@hua.gr, mpatzakis@hua.gr, dgriva@hua.gr)
  • 2Institut für Geowissenschaften, Universität Potsdam, Campus Golm, 14476 Potsdam, Deutschland (Julius.Jara@geo.uni-potsdam.de)
  • 3Eurasia Institute of Earth Sciences, Istanbul Technical University, Turkey (cyildirim@itu.edu.tr)
  • 4Départament des Sciences de la Terre, Université de Caen, 14032 Caen Cedex 5, France (kevin.pedoja@unicaen.fr)

Offshore islands may furnish valuable information regarding deformation rates, their controlling mechanisms, and the dynamics of the upper crust in offshore areas along subduction zones, which otherwise would be difficult to quantify by direct observations. Here we study active deformation and faulting at glacial-cycle time scales in the Kythera Island, located in the southwestern part of the Hellenic subduction zone, between Crete and the Peloponnesus. The Kythera Island exposes an outstanding sequence of more than twelve levels of marine terraces that depict the active uplift of the island. These terraces are offset by several NNW-SSE and NNE-SSW-oriented active faults. We use high-resolution topography combined with morphometric analysis to map the marine terraces and to estimate the heave and throw rates of the main faults on the island. We divide the marine terrace sequence into two groups, the higher marine terraces (260 – 480 masl) comprising composite rasa surfaces, and the lower terraces (20 – 220 masl) characterized by staircase morphologies. We focus on the two main faults of the island, defined as F1 and F2, which display right- and left-lateral and dip-slip displacements, offsetting the marine terrace risers and treads. We link the activity of these faults with the occurrence of intermediate-depth and strong magnitude earthquakes such as the Mw 6.6 and 6.7 that occurred in the area of Kythera in 1903 and 2006, respectively.  Further dating of marine terrace surfaces and structural analysis will be carried out in the next months in order to correlate the marine terraces with Marine Isotope Stages and to estimate heave and throw rates of the faults. Our work emphasizes the importance of carrying observations in islands to elucidate the deformation rates in offshore areas of subduction zones.

How to cite: Tsanakas, K., Jara-Muñoz, J., Karymbalis, E., Yildirim, C., Pedoja, K., Batzakis, D.-V., and Griva, D.: Quantifying active faulting using marine terraces, Kythera Island, Greece, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-369, https://doi.org/10.5194/icg2022-369, 2022.