The objective of this project is to develop a novel methodology for remote structural health monitoring that is robust when applied to actual structures and large amplitude response, and is calibrated using data from full-scale structures. The focus of this project will be on buildings. The methodology is based on detecting changes in travel time of seismic waves propagating through the structure, that have been radiated by a virtual source created by de-convolution of recorded vibration response. The methodology will be calibrated using earthquake records from full-scale buildings that have been damaged or could have been damaged by an earthquake. Further, the effectiveness of this methodology for general condition monitoring will be explored. The major advantages of this wave-based method are that it can localize the damage with relatively small number of sensors, and that it is not sensitive to the effects of soil-structure interaction and changes in other structural boundary conditions. The availability of a validated methodology that works with real structures and field data will greatly facilitate the decision making during emergency response and recovery following an earthquake, and will help reduce loss of life, injuries and monetary losses caused by earthquakes. For example, a timely decision to evacuate an unsafe building will reduce the risk of loss of life and injuries caused by potential collapse of the weakened structure by its shaking from the aftershocks. The methodology, with capability for general condition monitoring of structures, will be a useful tool in managing the aging infrastructure. The results of this project will be broadly publicized and reported in technical journals for information dissemination. The project will also enhance the educational infrastructure of the nation by training a graduate student working on her/his Ph.D. thesis.