EGU21-13441
https://doi.org/10.5194/egusphere-egu21-13441
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Kinematics of the Sea of Marmara using GPS, InSAR and underwater geodetic data: Possible Influence of Crustal Heterogeneity

Volkan Özbey1, Mehmet Sinan Özeren2, Pierre Henry3, Olivier Cavalié4, Xavier Le Pichon3, Elliot Klein5, Ergin Tarı1, and Gerald Galgana6
Volkan Özbey et al.
  • 1Istanbul Technical University, Department of Geomatics Engineering, Istanbul, Turkey (ozbeyv@itu.edu.tr)
  • 2Istanbul Technical University, Eurasia Institute of Earth Sciences, Maslak, Istanbul, Turkey
  • 3Aix Marseille Univ, CNRS, IRD, INRAE, Coll France, CEREGE, Aix-en-Provence, France
  • 4Géoazur, Université de Nice Sophia-Antipolis, CNRS, IRD, Observatoire de la Côte d’Azur, Valbonne, France
  • 5FM Global Research, Research Division, Norwood, MA, United States
  • 6Framingham State University, Department of Physics and Earth Science, Framingham, United States

Seismological studies on the western part of the North Anatolian Fault (NAF) revealed the possibility that it may constitute a bimaterial interface at various locations. One evidence for this came from Karadere and Mudurnu segments where Fault Zone Head Waves (FZHW) and Fault Zone Reflected Waves (FZRW) indicated bimaterial interfaces and damage zones of various depth ranges. These were often interpreted as factors affecting various aspects of rupture propagation velocities and rupture lengths. In addition, the difference in crustal structure between the northern shore of the Sea of Marmara and the deep basins may results in an effective rigidity contrast across the Main Marmara Fault, at least in its Eastern part from Kumburgaz Basin, to the entrance of Izmit Gulf. This could result in reduced elastic loading of the northern block, leading to an underestimation of slip deficit in geodetic models. However, the problem was never looked at using multiple constraints at the same time such as the GPS, InSAR and underwater geodetic data. In this study we use the interseismic slip distribution on the westernmost section of the NAF (comprising largely the Main Marmara Fault and the bifurcation zone to the east of the Izmit Gulf) obtained using a block model as a reference model and use a finite element model to test the perturbations to this model as a function of the elastic moduli contrasts across the fault. We are testing the case where there is a bimaterial interface all the way from Izmit Gulf to Kumburgaz and then a lack of such a contrast in the Central Basin. We are also investigating a scenario where the Ganos region also has bimaterial interface (but reverse in its nature).

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