Earthquake Damage Detection in Buildings and Early Warning Based on Wave Travel Times

This paper describes a novel method for structural health monitoring of buildings, currently being developed at the University of Southern California for future applications in earthquake early warning systems. The method uses data from vibrational sensors and is based on detecting changes in travel times of waves propagating through the structure. It is an intermediate scale method, which can point to the part of the structure that has been damaged using data from relatively small number of sensors. The method is illustrated using earthquake response data in two buildings damaged by earthquakes. The benefits to society from early warning systems of damage in structures, before physical inspection is possible, are discussed, both from the point of view of safety and from the point of view of avoiding needless service interruption.