The EEW system forecasts ground shaking after the
earthquake occurrence but before the arrival of seismic
waves, based on quick analysis of seismic data recorded
near the earthquake source. The EEW was developed
before 2004 but has been implemented and in
operation in the last decade in several countries such as
Japan [18]. Typical lead time between the announcement
and start of large ground shaking is from several to several
tens of seconds, yet providing useful information
through TV, radio or cell phones.