L. Li1 , C. Hao1
1Institute of Geophysics, China Earthquake Administration (CEA), Beijing, China
The waveforms of a 50t explosion that occurred on Dec. 11, 2007 and the nuclear explosion that occurred on Oct. 9, 2006 recorded by HIA (part of Global Seismic Network) and PS12 (station of the International Monitoring System) were analyzed. The distances between the two events to HIA and PS12 are over a 1000km, and the distance between HIA and PS12 is about 30km. PS12 is further away than HIA. Analyst results indicated that a borehole station can raised the SNR of P waves 4.7 times compared to the common station (for example, the nuclear explosion that occurred on Oct. 9, 2006), and the PS12 borehole array can depress noise 2.5 times (6 stations are usually in operation) by using beamforming, and can improve the SNR of a weak signal about 11.4 times compare to common stations. As to some other events (e.g. the 50t explosion that occurred on Dec.11, 2007), no signal was recorded at HIA while PS12 recorded the event and it could be used for location and analysis, which indicates the strong detection capability of a borehole array.