Izmit (Turkey) Earthquake of 17 August 1999: First Report

INTRODUCTION The earthquake of 17 August 1999 was the largest and most destructive earthquake to occur in Turkey since the 1939 Erzincan earthquake. The earthquake occurred on the western extension of the North Anatolian Fault, on a segment that has been identified as a “seismic gap.” The epicenter (40.76°N, 29.97°E, Kandilli) was near Izmit (Figure 1), at the eastern end of Izmit Bay, and the moment magnitude was Mw = 7.4 (USGS). The focal mechanism and the fault surface rupture indicate an east-west striking fault with pure right-lateral strike-slip motion. The eastern shores of the Gulf of Izmit, where the epicenter was, are densely populated, with extensive industrial and residential complexes. The earthquake devastated towns on the shores of Izmit Bay, Adapazari to the east, and a neighborhood in the western suburb of Istanbul about 150 km west of the epicenter. In the towns of Izmit and Golcuk, the destruction...