Application of a Threshold‐Based Earthquake Early Warning Method to the Mw 6.6 Lushan Earthquake, Sichuan, China

Mitigation of earthquake damages remains an open task, despite the fact that many solutions have been proposed in the recent past. In this framework, the so‐called earthquake early warning systems (EEWS) try to exploit the short time interval between the earthquake occurrence and the arrival of the destructive wavetrain to warn the population or to perform some automatic actions that can reduce damages induced by the ground shaking. A rapid analysis of real‐time data from seismic stations deployed in the source region is the key element in such system. During the last three decades, the EEWS is increasingly used to reduce exposure of populations to seismic risk, and several countries around the world have already developed EEWS, or are on the verge of doing so. Japan, Taiwan, Mexico, and California, for example, already have operational EEWSs (Wu and Teng, 2002; Horiuchi et al. , 2005; Wu and Zhao, 2006; Hoshiba et al. , 2008; Espinosa‐Aranda et al. , 2009). In particular, the EEWS developed by the Japan Meteorological Agency began to send early‐warning information to general public since 2007. EEWSs are also under development and testing in other regions of the world, including Italy, Turkey, Romania, and China (Allen and Kanamori, 2003; Bose et al. , 2007; Alcik et al. , 2009; Allen, Brown, et al. , 2009; Allen, Gasparini, et al. , 2009; Bose et al. , 2009; Zollo et al. , 2010; Peng et al. , 2011; Satriano et al. , 2011; Kuyuk et al. , 2014). Most EEWS are designed as either regional (or network‐based) or onsite (or station‐based) systems. Deployment of the EEWS essentially depends on network geometry and source‐to‐site distance. In a regional EEWS, the early portion of recorded signals is used to rapidly estimate source parameters (event location and magnitude) and to …