Regional Seismic Event Characterization Using a Bayesian Kriging Approach
SOUTHERN METHODIST UNIV DALLAS TX
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This effort focuses on collecting and analyzing regional seismic data for earthquakes and underground explosions to improve seismic event characterization capabilities with regard to monitoring the Comprehensive Nuclear-Test-Ban Treaty CTBT. Digital data have now been acquired and processed for 267 regional recordings of 160 underground nuclear UNE and chemical UCE explosions. The explosion data set includes 99 Nevada Test Site NTS UNEs recorded by MNV and KNB 6 Lop Nor UNEs recorded by NIL, ZAL, ULN, WMQ, BRVK and MAKZ 22 Semipalatinsk STS UNEs recorded by WMQ and BRVK 6 Novaya Zemlya NZ UNEs recorded by ARCES and KEV and one UNE at the Indian Test Site recorded by NIL. In addition, the set includes 20 Former Soviet Union FSU peaceful nuclear explosions PNE recorded by BRVK and KEV and 6 STS UCEs recorded by ZAL and BRVK. Note not all of these explosions have recordings by all stations listed. Over 5300 regional recordings, between 3 and 17 degrees, by existing seismic stations of the International Monitoring System IMS are also used in this study. The regional recordings correspond to 4173 presumed earthquakes above mb 3.5 in the Reviewed Event Bulletin REB that were processed at the prototype International Data Center pIDC. Maximum amplitude measurements of Pn, Pg, Sn and Lg have been computed in several frequency bands ranging from 2 Hz up to 14 Hz depending on the Nyquist frequency of a given station. The data for the presumed earthquakes have been used to estimate attenuation corrections for PnSn and PnLg amplitude ratios in the 2-4, 4-6, 6-8, and 8-10 Hz passbands for tectonic and stable region types. The regional phase amplitude ratios are further corrected for path variations using a Bayesian Kriging algorithm.
- Statistics and Probability