Geotechnical aspects of damage in Adapazari City during 1999 Kocaeli, Turkey earthquake

Reported are the results of a detailed investigation of the structural damage and its geotechnical condition in the Adapazari City, Turkey, during the 1999 Kocaeli earthquake by the Japanese Geotechnical Society Reconnaissance Team. Damage to individual buildings was investigated along several streets in the downtown area. A regional investigation was made of an area larger than the downtown area, in which damage to buildings and houses was classified by cause, i.e., inertia force or ground deformation. These investigations as well as hearing investigation and aerial investigation by means of helicopters made clear the area where there was an island a few hundred years ago from which the name of Adapazari, i.e., ada (island) + pazari (market), came from. In addition, the damage in the Adapazari City is shown to be strongly affected by the ground condition because damage caused by liquefaction was observed only outside the old island and areas where significant structural damage was observed were concentrated in the nonliquefied area near the boundary between the old riverbed and island.