Experiment on an Onsite Early Warning Method for the Taiwan Early Warning System

As increasing urbanization is taking place worldwide, earthquake hazards pose serious threats to lives and property in urban areas. For seismic hazard mitigation, a practical earthquake forecast method appears to be far from realization, because of the extreme complexity involved in earthquake processes (e.g., Kanamori et al., 1997). Another approach to mitigate seismic hazards is the development of early warning systems (ews) (Nakamura, 1984, 1988; Heaton, 1985; United States National Research Council, 1991; Teng et al., 1997; United States Geological Survey, 1998; Wu et al., 1998; Wu and Teng, 2002; Allen and Kanamori, 2003). An ews provides a few seconds to tens of seconds of warning time for impending ground motions, allowing for mitigation measures in the short term. Early warning systems that estimate the severity of ground shaking and its onset time are in operation in Japan (Nakamura, 1984, 1988, 1989), Mexico (Espinosa-Aranda et al., 1995), and Taiwan (Teng et al., 1997; Wu et al., 1998, 1999; Wu and Teng, 2002). This timely information can be used to minimize property damage and the loss of lives in urban areas. It can also be used for real-time loss estimation to aid emergency response and recovery (Wu et al., 2002).