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ASSESSMENT OF STATION CORECTIONS (SITE-EFFECT) FOR SEISMIC STATIONS FROM THE BULGARIAN SEISMIC NETWORK CALCULATED ON THE BASIS OF LOCAL AND REGIONAL EARTHQUAKES
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E. Oynakov; D. Solakov; I. Aleksandrova
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1314-2704
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English
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21
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1.1
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• Prof. DSc. Oleksandr Trofymchuk, UKRAINE
• Prof. Dr. hab. oec. Baiba Rivza, LATVIA |
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The present study focuses on the assessment of station corrections for eleven seismic stations from the national network of National Operative Telemetric System for Seismological Information (NOTSSI). Station corrections are obtained by calculating the ratio of the spectrum of the horizontal components of the signal to the spectrum of the vertical component (H / V). Records of S-waves from 20 local and regional earthquakes are analyzed. The values of A0 - site-effect and f0 - resonant frequency were obtained. According to the type of obtained H / V- ratio curves, the studied seismic stations from the NOTSSI network can be divided into two groups. The first group includes stations with stable amplitude-frequency characteristics of the seismic signal - PRD, PLN, PLD, KDZ, MMB, KKB and VTS1. The resulting H / V ratio curves are close to straight lines with an amplitude of a unit. The second group of seismic stations are stations with medium level of amplification (2-3 times) - SZH, TRAN and PSN. The highest amplification for these stations is at frequencies from 4 to 4.5 Hz, which is probably an evidence of low impedance contrast between the foundation and the deposits. Polarization analysis for seismic stations is presented in order to study the influence of the location of the source (i.e. the azimuth from the source) on the level of motion amplification in the surface layer of the location. The obtained results give grounds for the conclusion that most stations in the network are "good" - i.e. no increase in the amplitudes of the recorded signals is observed due to resonant phenomena.
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conference
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21st International Multidisciplinary Scientific GeoConference SGEM 2021
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21st International Multidisciplinary Scientific GeoConference SGEM 2021, 16 - 22 August, 2021
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Proceedings Paper
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STEF92 Technology
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SGEM International Multidisciplinary Scientific GeoConference
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SWS Scholarly Society; Acad Sci Czech Republ; Latvian Acad Sci; Polish Acad Sci; Serbian Acad Sci & Arts; Natl Acad Sci Ukraine; Natl Acad Sci Armenia; Sci Council Japan; European Acad Sci, Arts & Letters; Acad Fine Arts Zagreb Croatia; Croatian Acad Sci
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411-418
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16 - 22 August, 2021
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website
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cdrom
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7806
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site-effect; seismic station; amplification; spectrum; earthquake
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