Abstract
In order to evaluate the soundness of gravity concrete dams, the dynamic characteristics are estimated by seismic observations. However, it takes a lot of time to acquire seismic observation records. There are also a limited number of dams where seismometers are installed. Therefore, the dynamic characteristics of dams are being estimated by microtremor measurement. However, it is hard to say that sufficient investigations have been made on the relationship between the dynamic characteristics obtained from earthquake records and those obtained from microtremor measurements. In particular, since there is almost no artificial vibration source in the mountainous area where the dams are located, the level of microtremor is very small, and there is a question as to whether the structures are sufficiently excited. Therefore, in this study, microtremor measurements were performed at the concrete gravity dams where seismometers are installed to evaluate the dynamic characteristics, and compared with the results obtained from seismic observation records.
