Abstract:Accurate earthquake prediction is still a far-reaching goal for modern seismology because of the complicated seismogenic process and and rupture initiation process.More reliable and rewarding measures are seismic risk assessment and enforcement of building code before earthquake.Implementation of early warning system(EWS) for strong earthquakes and rapid seismic damage mitigation are the two major components of real time seismology.EWS takes the advantage of time difference between the fast propagating weak P waves which carries definitive information of strong earthquakes,and the later arriving damaging S waves.With only a few to tens of seconds,magnitude and location of an earthquake can be estimated with the initial portion of P waves,and early warning is issued to avoid damages.Then within hours,global waveforms can be inverted to get the detailed process of seismic energy radiation,a reliable map of ground shaking can be calculated based on the inverted models with verification from strong motion records.For the dense network in Eastern China,20 seconds early warning is realizable.