Engineering and Organizational Issues Related to the World Trade Center Terrorist Attack Michel Bruneau, Andrew Whittaker, Andrei Reinhorn, Jeffrey Berman, Gordon Warn Department of Civil, Structural, and Environmental Engineering University at Buffalo, Buffalo, NY 14260 United States and Charles Huyck, Beverley Adams ImageCat, Inc, Long Beach, California 90802 United States Abstract The Multidisciplinary Center for Earthquake Engineering Research (MCEER) collected perishable data in the aftermath of the attack for later study to gain a better understanding of how resilience is achieved in both physical, engineered systems and in organizational systems. The results of the engineering-related aspects of this work to date are briefly summarized in this paper. Keywords: World Trade Center Attack, damage reconnaissance, structural evaluation, structural performance, push-over analysis, emergency response, research, remote sensing. 1. Introduction The terrorist attack that took place on September 11, 2001 in New York City resulted in thousands of lives lost, the collapse of the twin towers of the World Trade Center as well as damage to adjacent buildings, and extensive disruption of transportation and other lifeline systems, economic activity, and other social activities within the city and the surrounding area. When the final accounting takes place, this attack will almost certainly constitute one of the most deadly and costly disaster events in U. S. history. In a very real sense, the September 11 tragedy, the nature of the damage that occurred, the challenges that the city's emergency response faced, and the actions that were undertaken to meet those demands can be seen as a "proxy"-albeit a geographically concentrated one-for what a major earthquake can do in a complex, densely-populated modern urban environment. Like an earthquake, the terrorist attack occurred with virtually no warning. As would be expected in an earthquake, fires broke out and multiple structural collapses occurred. As has been observed in major urban earthquakes and in other disasters (e.g., Hurricane Andrew), structures housing facilities that perform critical emergency functions were destroyed, heavily damaged, or evacuated for life-safety reasons. Additionally, because the majority of the damage occurred to relatively new and well-engineered structures and because the emergency response system in New York City was considered very well prepared for all types of emergencies, particularly terrorist attacks, the attack and its aftermath provide a useful laboratory for exploring a variety of engineering and emergency management issues. In this perspective, the Multidisciplinary Center for Earthquake Engineering Research initiated a research project (funded by the National Science Foundation) to collect perishable data in the aftermath of the attack for later study to gain a better understanding of how resilience is achieved in both physical, engineered systems and in organizational systems. The project is divided into two major components, focusing on the impact of the disaster on engineering and organizational systems: