Earthquake Hazard Mitigation and Real-Time Warnings of Tsunamis and Earthquakes

With better understanding of earthquake physics and the advent of broadband seismology and GPS, seismologists can forecast the future activity of large earthquakes on a sound scientific basis. Such forecasts are critically important for long-term hazard mitigation, but because stochastic fracture processes are complex, the forecasts are inevitably subject to large uncertainties, and unexpected events will inevitably occur. Recent developments in real-time seismology helps seismologists cope with and prepare for such unexpected events, including tsunamis and earthquakes. For a tsunami warning, the required warning time is fairly long (usually 5 min or longer) and enables use of a rigorous method for this purpose. Significant advances have already been made. In contrast, early warning of earthquakes is far more challenging because the required warning time is very short (as short as three seconds). Despite this difficulty the methods used for regional warnings have advanced substantially, and several systems have been already developed and implemented. A future strategy for more challenging, rapid (a few second) warnings, which are critically important for saving properties and lives, is discussed