Failures of structures during the October 23, 2011 Tabanlı (Van) and November 9, 2011 Edremit (Van) earthquakes in Turkey

The October 23, 2011 Tabanlı and November 9, 2011 earthquakes that hit Tabanlı and Edremit districts of Van province in Turkey and their impacts on different types of structures are studied in this paper. According to United States Geological Survey (USGS), the magnitudes of these earthquakes, which caused partial or total collapse of numerous buildings and more than 600 casualties, were 7.1 and 5.6, respectively. Other than negatively impacting all aspects of daily life, the earthquakes remarkably disrupted the economical activities in the area. This paper summarizes the seismological characteristics of the affected region, the general characteristics of the strong ground motion and the types of structural damage observed during site investigations. Emphasis is given to the failures and seismic performance of different types of structures, through detailed explanation of damage mechanisms. The structural damage levels are observed to be directly related to the extent of irregularities of the structural system, level of the insufficient quality in the workmanship, and usage of inadequate building materials. It was also clearly observed that if a minimum amount of engineering attention had been paid during the construction stages, and the requirements of design and construction codes had been satisfied, most of the existing buildings could have sustained the earthquakes without considerable damage.