INTAS-IA-96-03 - Moscow: July'98 -
a few words on the available seismic DATA SET at Spetsgeofizika
(click on images for a larger view)

This is a partial map of the seismic data now available in the paper-archive of  Spetsgeofizika's  Office.

         Their priority in the processing process (due to the local scientific needs) is the following:
Spetsgeofizika seismic data: map of available profiles (TNT sources)
N.
Label
Direction
Length
(km)
N. of 48-ch.
sheets
1
XX
 Tsimlansk-Peschanokopskaya
340
1000
2
XVII
 Elista-Shakhti
250
700
3
V-N
Volgograd-Nakhichevan
800
(°) 

The first line to process will be the Profile XX, a straight-line of 340 km length, which crosses the Scythian Plate in the south, the Karpinsky Swell and stretches into the Voronezh Massive at its northern end (see map). This profile was carried out in 1973-'74, using 23 shot points, direct and reversed shooting (TNT explosions in bore-holes combined in groups, 25-30 m deep, ca. 40 kg. each). Groups of 5 geophones with dominant frequency of ~10 Hz were used, spaced 100 m. The available photographic papers have been recorded by wiggle trace method, using high-cut filter (~15 Hz). Other data could be available somewhere else: a detailed search for further information will be carried out, contacting other Russian institutions, in order to discover other possible data. But up to now (°) the preliminary searches of the original data have been negative, and nobody knows if they do still exist somewhere or have been destroyed. Remember: here we are dealing only with traditional data, in the sense of type of chemical energy source: that means TNT explosion. Other non-traditional data (obtained by peace nuclear explosions in the sixties-eighties) used to produce incredible long seismic profiles, are still collected and available at GEON Centre, another well known state research enterprise.

Spetsgeofizika: observing the traces...
    Mr Yurov and Mr Zeyen are observing some papers and making a first rough check of the quality of the data .

    These will then be processed as follows: after the best parameters-choice, they will be acquired as Image-form by the A0-Scanner. Normally each paper consists of 48 traces (that means about 4800 m of in-line deployment), and a profile is a collection of several tens of them.... Then, with the selected Software package (DGS, by Synapse), from each image the single seismograms are extracted  (Vectorization phase): this is the heart of the whole system, and the final success will depend Synapse software applied: DGS result !Spetsgeofizika example 1mostly from the accuracy of this step; the two  figures represent the first successful test on DGS procedure (left: Input; right: Output data).

  Finally, using another standard seismic package (SAC-2000), with a little programming intervention to take into account our large delay-times, the common 'section-film' will be produced, in a reduced-time version, using proper reduction velocities (normally 6.0 km/s for distances up to ca. 200 km; 8.0 for longer distances).

Spetsgeofizika: hand-made processing (sixties...)
This is a very nice example of the old data hand-made processed in the sixties. The quality is very good, but one did spent some weeks of work to produce a copy like this one (you see: re-draw by hand one seismogram every 20 or more...) and, at the end of job, only this unique copy was available for the geophysical studies and interpretation.... If it should had been necessary to remake another section with some of the 'processing' parameter modified (reduction velocity, amplitude scale, time-window, etc.), all the procedure should had to start again....
 


References
The Central Europe's DSS data have been widely used to improve the Crust definition and its geophysical global structure. For a general view of the European efforts, see the Europrobe Projects. For a specific example of a study in an adjacent area, see the Dniepr-Donets Rift deep structure study, by T.Ilchenko.