Location performance of a sparse regional network

A key element in successful seismic verification of a nuclear test ban treaty is the capability of a sparse network of seismic stations to accurately locate regional events. We have investigated the regional location accuracy of the Regional Seismic Test Network (RSTN), a five‐element, three‐component network in eastern North America, using 62 events varying in size from magnitude 3.0 to 5.1. Applying an algorithm which allows inclusion of back‐azimuth estimates as well as travel times, we determined a median location error of 23 km for the data set relative to the PDE locations. Considering the large station spacing (1500 km) and few data used in the locations (2 to 4 stations), the RSTN location accuracy is remarkably good; the results imply that a widely spaced network of single, three‐component stations could reliably locate regional seismic events.