The tsunami of August 17, 1999 in Izmit Bay, Turkey

The Kocaeli 1999 Earthquake with an Mw = 7.4 caused major hazards throughou t the NW of Turkey from Tekirdag to Bolu. Historical data indicates that so me of the earthquakes around Izmit Bay have caused tsunamis. In this study, tsunami research for the Kocaeli 1999 Earthquake has been made also taking into consideration historical data. In this research more than about 70 da ta at 35 localities have been used to determine the tsunami evidences in th e bay. Coastal observations indicated runups which were ranging from 1 to 2 .5 m along the shores. However, the wave runups are more complex along the south coast due to the presence of coastal landslides (Degirmendere, Halide re, Ulasli, Karamursel) and subsided areas (Kavakli to Yenikoy) along the s hore. West of Yalova, evidence of tsunami rapidly diminished. In addition, possible tectonic mechanism has been determined by using 33 single-channel high-resolution digital seismic reflection profiles which were acquired fol lowing the Kocaeli 1999 Earthquake. As a result it has been determined that the Kocaeli Earthquake has created tsunami in Izmit Bay.