Determination of mislocation vectors to evaluate bias at GSETT-3 primary stations

Using the database provided by the Reviewed Event Bulletins (REBs) for the first 2.5 years of the Group of Scientific Experts Technical Test-3 (GSETT- 3) experiment, we compiled mislocation vectors for both arrays and selected three-component stations of the primary network from the published slownes s and azimuth information gained through f-k- and polarization analysis. Im posing constraints such as a minimum signal-to-noise ratio (SNR) and number of defining phases, we aim at eliminating location bias as the hypocentral parameters are taken from the REBs. Results from 14 arrays with apertures from about 1 km to more than 20 km are presented as well as from 18 three-c omponent stations, which indicate that the mislocation vectors in many case s can improve location accuracy considerably. If these mislocation vectors are compiled to provide coverage of a sufficient portion of the slowness do main these empirical corrections can easily be applied prior to location pr ocessing. In the context of the Comprehensive Nuclear Test-Ban Treaty (CTBT ), these mislocation patterns could be essential for providing accurate eve nt location of suspicious low-magnitude events, as these location parameter s will be used to pinpoint the area where to conduct an on-site inspection.