Improvements to a Major Digital Archive of Seismic Waveforms from Nuclear Explosions: The Borovoye Seismogram Archive

摘要

We are in the final year of a three-year project to generate in modern form an easily usable archive of digital seismograms derived from regional waveforms recorded at the Borovoye Observatory (BRV), northern Kazakhstan, over a thirty-year period going back to 1966 and forward to the time when state-of-the-art sensors and dataloggers were introduced at this site by several different western groups. The BRV seismograms, which include multi- channel regional signals from 350 underground nuclear test explosions carried out in Eurasia, were made generally available to western scientists in 2001, but only as copies of the bits in the original digital waveforms. Those copies contain large numbers of glitches and did not include instrument responses for approximately two-thirds of the events. Our project is a joint effort by scientists at Lamont-Doherty Earth Observatory of Columbia University (LDEO) and at Los Alamos National Laboratory (LANL). The work of deglitching all the Borovoye digital seismograms has now been completed (at LANL). The initial work of determining instrument responses for the many different channels of the three different digital systems used at Borovoye over the thirty-year period has also been completed (at LDEO). Three different sets of Soviet-style instruments and recording systems were used at BRV from 1966 to 1996. LANL scientists had processed the BRV regional signals for 210 nuclear tests (1355 traces) before the present project started, mainly those for which instrument responses were available (the TSG system). In this project LANL processed the waveforms of the so-called SS system for 148 nuclear tests (1679 traces), some of which were also recorded on the TSG system, and these have now been processed too (281 traces). The remaining main block of events was recorded on the oldest, so-called KOD, system, which was used in operations beginning in 1966 and which operated continuously from 1967 to 1973.