More than 30 tsunami events have impacted the coasts of the Sea of Marmara in the past two millennium, clustering in Izmit Bay, the shores of istanbul, Gemlik Bay, the shores of the Kapidak and Gelibolu Peninsulas. With respect to the last well-known tsunami, the Izmit tsunami of 17 August, 1999, available field survey run-up data and marine surveys provide an opportunity to evaluate how these events were triggered. The main purpose of this study is to determine the slope failure potential as a possible tsunamigenic source in the Sea of Marmara by utilising multi-beam bathymetry, shallow and deep seismic reflection data. On the basis of the landslide geomorphology, the generation, propagation and coastal amplifications of tsunamis related to earthquake and slope failure scenarios were tested by using tsunami simulation model TWO-LAYER. The maximum water surface elevations near the shores along the north and south coasts are obtained according to the selected scenarios of tsunami generation by using available data. (C) 2002 Elsevier Science B.V. All rights reserved.