Preface for the special issue on Seismic Structural Health Monitoring for the Bulletin of Earthquake Engineering.

In the last thirty years, Seismic Structural Health Monitoring (S SP 2 sp HM) has received a growing interest from both researchers and professionals, and an increasingly high number of seismic monitoring systems are currently installed in various countries. Therefore, the paper B Liao et al. b shows that medium-quality accelerometers (MEMS-based instruments) can provide feasible solutions for cost-effective city-scale deployment and performances that are superior to those of sensor networks with high-quality accelerometers. Vibration-based damage identification techniques are thus an important decision support tool that is being investigated by several research groups using both data-driven and model-based approaches. [Extracted from the article]