caa a22 4500 463172361 CHVBK 20180406164817.0 cr unu---uuuuu 170326e20070401xx s 000 0 eng 10.1007/s10950-006-9044-9 doi (NATIONALLICENCE)springer-10.1007/s10950-006-9044-9 Douglas A. AWE Blacknest, Brimpton, RG7 4RS, Reading, UK aut Source bias in epicentre determinations revisited [Elektronische Daten] [A. Douglas] Most estimates of the epicentre of the Long Shot explosion (29 October 1965, Aleutian Islands) are biased to the north of the true epicentre, this bias being much larger than formal uncertainty estimates. The bias is interpreted by some as evidence that the P-wave speeds in the upper mantle in the source region are higher to the north than to the south; that is, the difference between estimated and true epicentre is a source bias. Others argue that much of the bias can be explained by station anomalies, i.e. differences in the wave speeds in the upper mantle at stations to the north relative to those to the south. Bias may also be introduced by measurement error if signal-to-noise ratio (SNR) is lower on average at stations to the south compared to those to the north and times are read late at the low SNR stations. Here I locate Long Shot and the other two Aleutian Island explosions (Milrow and Cannikin) using P times from small networks of stations all on continents. The results support the view that a large component of the bias in the epicentres of the three explosions is due to station anomalies and not source bias, but that for the Long Shot explosion (the lowest magnitude of the three explosions), measurement error due to systematic variations in the SNR between stations to the north and south also contributes to the bias. Springer Science+Business Media, Inc., 2007 P waves nationallicence epicentre bias nationallicence nuclear explosions nationallicence Journal of Seismology Kluwer Academic Publishers 11/2(2007-04-01), 171-176 1383-4649 11:2<171 2007 11 10950 https://doi.org/10.1007/s10950-006-9044-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10950-006-9044-9 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Douglas A. AWE Blacknest, Brimpton, RG7 4RS, Reading, UK aut NATIONALLICENCE 773 0- Journal of Seismology Kluwer Academic Publishers 11/2(2007-04-01), 171-176 1383-4649 11:2<171 2007 11 10950 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer