ABOUT IDENTIFICATION OF INDUSTRIAL EXPLOSIONS BY THEIR RECORDS AND THEIR CONNECTION WITH WEAK SEISMISITY  Fulltext 

[ Sargsyan Heghine ] - Chief seismologist in “Northern Survey for Seismic Protection” State non commercial organization, Republic of Armenia, V. Sargsyan 5a, Gyumri, 377500, Republic of Armenia
[ Sahakyan Ashik ] - Director in “Stepanavan” station
[ Nahapetyan Hasmik ] - Northern Survey for Seismic Protection”, Armenia, V. Sargsyan 5a, Gyumri, 377500, Republic of Armenia

خلاصه مقاله:

The extension and improvement of the seismological observation net on Caucasus allowed to register and treat seismic events of low power levels. In this connection it seems possible more in a broad power range of the initial experimental material the solution of the problem connected with seismic mode and with the evaluation of seismic hazard, especially in temporary definitions of local earthquakes has appeared. The seismological report and catalogue of industrial explosions are composed by us. The data bases of the initial experimental materials for testing in different algorithms are created. In the Caucasus the detailed researches brings to the selection of fictitious source zones, which hit in the catalogue of data as earthquakes. Therefore we delivered the problem to develop a method of selection of industrial explosions from weak earthquakes. On the base of records: SSM-3 and FMSS in seismic station "Stepanavan", SSM-3 in stations "Karmrakar", "Kadjaran", " Vardenis" and Yerevan is conducted the "cleaning" of main parameters of earthquakes of the catalogue from industrial explosions. The statistical analysis of seismological material allowed to select the high seismicity which peak was in 12 o’clock (by Greenwich), and the square was divided into this zones: Near the Elbruss, Dashkesan and Kadjaran . In this zones is declined the linearity of the schedule of recurrence. The grouping of events with M< 3 is observed. Among dynamic characteristics of explosions are selected the following qualitative and quantitative indications: 1. On a vertical component (Z) the wave of compression enters. 2. On horizontal components the entrance of P wave as a rule is less precise. 3. The wave S practically is polarized. And the oscillation of this wave happens near the vertical plane. 4. By FMSS data (frequency measuring seismic station) the relation of maximum amplitudes of longitudinal and transversal waves with the coefficient of correlation 0,9, where 0,2 < f< 30 (Hz). 5. The peak spectra of FMSS have shown, that since 5 Hz Ap > As 6. By the average of FMSS codes of wave from explosions damp faster, than from earthquakes. The Aioo for explosions from 0,6 Hz monotonically is increased, and for earthquakes has a various character, that is stipulated by complicated source radiation. 7. After the Spitak earthquake from the values of the parameters of seismic regime the most strongly change was observed at “n”- seismic background. The quantity of weak earthquakes, which was normalized on the unit square and time, decreased. The investigations showed that the activation of weak seismicity is closely connected with the industrial explosions, which were executed every day in seismoactive zones before the Spitak earthquake. For the recognition of explosion from the weak earthquake was made up the catalogue of industrial explosions and weak earthquakes for each zone. For each zone was made up a histogram for earthquakes and explosions. The explosions of the Northern part of Armenia in the district “Stepanavan” aren’t distinguished from the weak earthquakes of the given district. Only the remote, from the source, explosion records can be distinguished as explosions. The explosions of the rest seismic active zones are distinguished by their damping and high frequency.