25 Seconds for Bucharest

Abstract

The Romanian capital Bucharest faces a signifi? cant earthquake hazard with a 50% chance for an event greater than 7.6 moment magnitude within 50 years. The last devastating earth? quake hit in 1977 when 35 high-rise buildings were destroyed and 1500 fatalities were counted. An Early Warning System (EWS) based on the traveltime differences between the primary P-wave and the destructive S-wave al? lows a warning time of about 25 s. Peculiarities of the Romanian intermediate depth seismicity such as the stationary epicenters and the stabil? ity of radiation patterns, and a line-of-sight connection between the epicentral area and the capital allow to design a simple and robust EWS. Simplicity and robustness of the system are sought in order to reduce the risk of false alarms, which is crucial for making the system cost-beneficial.