Issues

Front: The first stage of the Korean Earthquake Early Warning System began operations in January 2015, with the goal of issuing a warning within 50 seconds 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, all for earthquakes greater than magnitude 5.0. “The First Stage of an Earthquake Early Warning System in South Korea,” by Sheen et al. (this issue), reviews the system’s performance and reports on its responses for recent offshore and inland earthquakes. Back: “The McAdam, New Brunswick, Earthquake Swarms of 2012 and 2015–16: Extremely Shallow, Natural Events,” by Bent et al. (this issue), reports on the many recent earthquakes that have occurred within a 1–2 km² area of this village in eastern Canada, as well as the instrumentation and data collected to investigate the seismic activity. The authors report that no faults are mapped close to McAdam, but that events might have occurred on a NW–SE splay of the Fredericton fault. They also report that there was no human activity that could have induced or triggered the swarm, and that the cause remains unexplained.