The First Stage of an Earthquake Early Warning System in South Korea

The first stage of the Korean Earthquake Early Warning System (KEEWS) began operations at the Korea Meteorological Administration in January 2015. The goal at this stage is to issue a warning within 50 s of detecting an earthquake of magnitude 5.0 or more. Since operations began, all local earthquakes of magnitude 3.0 or greater have been detected with sufficient accuracy. In the two years since operations started, three warnings have been issued, including for an offshore earthquake of magnitude 5.0 that occurred on 5 July 2016 and for two successive magnitude 5.1 and 5.8 earthquakes that occurred in the southeastern Korean Peninsula on 12 September 2016. In this article, we introduce the KEEWS and review its performance from January 2015 to July 2016. We also report on its responses for recent offshore and inland earthquakes.