Current Status of Strong-Motion Monitoring and Notification at the United States Bureau of Reclamation

Acquisition of strong motion data at the Bureau of Reclamation provides near real time notification of strong shaking at our structures as well as recordings of earthquakes for use in the dynamic analyses of large, engineered structures. To facilitate rapid notification following strong ground shaking, we have developed a low-cost, automated system to retrieve event-triggered seismic waveform data from digital data loggers at remote sites. Only a modest infrastructure investment is required. The method relies on standard dial-up telephone circuits, a custom-designed serial interface device, and communications software that runs under a UNIX operating system. Event wave- forms can be retrieved in near real-time from strong-motion accelerographs as well as from general-purpose seismic data loggers. The system can perform automatic remote configuration and periodic state-of health monitoring of the field instrumentation. The system presently retrieves data from 70 digital strong-motion instruments at 49 dams and other lifeline facilities located throughout the western United States. It has also been successfully used in temporary site-response and aftershock studies to provide remote access to seismic data loggers with broadband seismometers. Deployment of instrumentation is also focused on acquiring the detailed recordings necessary for validating the increasingly sophisticated dynamic analyses of dams.