资源环境科技发展态势分析平台

Precisely locating sites of nuclear tests is important for the Comprehensive Nuclear-Test-Ban Treaty and structure studies. Here we apply a relative relocation method to a dense regional seismic array, Hi-net, to determine the relative locations of the sites of the North Korean nuclear tests from 2006 to 2017. Our results show that the sites of the 2013 to 2017 events are closely located together and within 600 m of the site of the 2009 event. The site of the 2006 event is located similar to 2 km southeast to the site of the 2009 event. A bootstrap resampling of azimuthal subsets of the array adds confidence to the relative locations. Seismic data recorded at regional distance by a dense network with azimuthal coverage as limited as 80 degrees can resolve the relative locations of the nuclear tests to within a few hundred meters for all but the 2006 event. This approach can be extended to locating natural earthquakes as well.

Plain Language Summary Precisely locating sites of nuclear tests is important for global Nuclear-Test-Ban Treaty. Here we apply a relative relocation method to a dense regional seismic array (Hi-net) to determine the relative locations of the sites of the North Korean nuclear tests from 2006 to 2017. Our results show that 2013 to 2017 events are closely located to the site of the 2009 event. The site of the 2006 event is located similar to 2 km southeast to the site of the 2009 event. The results are further validated by a bootstrap resampling of azimuthal subsets of the array. We show that a dense seismic network with azimuthal coverage as limited as 80 degrees can resolve the relative locations of the nuclear tests. This method can be applied to many offshore earthquake clusters for better relocations as well. Precise locations of the earthquake cluster will better illustrate the offshore faults that are seldom well investigated.