Estimating the location accuracy of the Beijing Capital Digital Seismograph Network using repeating events
首都圈地区“重复地震”及其在区域地震台网定位精度评价中的应用

Location capability and its spatial distribution of the Beijing Capital Digital Seismograph Network were estimated using 'repeating earthquakes' or 'earthquake doublets' from 2002 to 2006.Taking the definition of waveform correlation by Schaff and Richards1],it is assumed that the 'repeating events' or 'doublets' are separated by no more than 1km,the network-measured apparent distances of 'doublets' indicates the order of magnitudes of the location error,and the difference of travel times between the 'repeating events' indicates the error of phase picking.Waveforms of 0.5~5.0 Hz band-pass filtered BB/VBB recordings and 1.0~5.0 Hz band-pass filtered SP recordings are cross-correlated,recognizing 859 'repeaters',being 24% of the whole events.It is observed that the average accuracy of the routine location by the Beijing Capital Digital Seismograph Network is of the order of magnitudes of 5km in the northern part where seismic observational condition is better,and of 13km in the south and west part where seismic observational condition is to be improved.