STRUCTURAL FEATURES OF THE TUZLA REGION, ISTANBUL

Structural features of the Tuzla region, Istanbul

Mehmet Bas, Bedri Alpar

Yunus Emre Cad. 15/13 Maltepe, Istanbul, TURKEY
Istanbul University, Institute of Marine Sciences and Management, 34116 Vefa, Istanbul, TURKEY

Abstract

All known earthquakes which affected Istanbul are originated in the Sea of Marmara, while there is not any large earthquake occurred on land on the Kocaeli Peninsula. Small scale earthquakes located on this platform have become much more interesting to researchers after two 4.2 Ms events occurred along the Tuzla-Pendik coastal area after the disastrous 17 August 1999 earthquake. Some NE-SW trending lineaments on the Kocaeli Peninsula are evident from digital elevation models and satellite images. The valleys along these lineaments show low resistivity and shear wave velocities, implying buried discontinuities. Seismic studies showed that the associated discontinuities observed in the acoustic disturbance at sea may be some of the faults on which the modem Sea of Marmara evolved. In present, the old faults in the Palaeozoic basement may be reactivated by the earthquakes occurring along the North Anatolian fault zone, causing damage to the settlements along the alluvial valleys extending inland.

Keywords: Sea of Marmara, tectonic setting, fault, seismic reflection, earthquake, underwater failures