USING GEOMECHANICAL MODELING TO CONSTRAIN THE 3-D FAULT GEOMETRY WITHIN THE WESTERN MARMARA SEA, TURKEY
This paper presents a method for characterization of 3-D fault geometry within the Marmara Sea from observed displacements on the seafloor or stratigraphic horizons. Our method, based on linear elastic fracture mechanics, utilizes three-dimensional boundary element modeling software (Poly3D). In our model, faults within a specified 3-D geometry are allowed to slip in response to regional stress loading conditions for the Marmara Sea region. Then, fault slip distributions and subsequent displacements on grid surfaces are computed. These grid surface displacements are compared to observed Marmara Sea bathymetry as well as the deformed pre-transform/syn-transform stratigraphic horizons mapped from 2-D seismic reflection profiles. Results to date for the western Marmara Sea suggest that the fault geometry in the Tekirdag basin region requires lateral bounding faults as well as the large east-west trending faults to the north and south to produce the basin geometry observed in the seismic and bathymetry data. This predicted geometry is in contrast to the simpler single fault hypothesis put forth recently by several authors for the western Marmara Sea.