Seismic Microzoning Method with using procedures by spectrum ratio H/V

• Main Authors: Senin, L., Senina, T., Voskresenskiy, M.
• Format: Article
• Language: rus
• Published: Subbotin Institute of Geophysics of the NAS of Ukraine 2020
• Subjects: seismic microzoning; spectral analysis; procedures of spectrum ratio; seismogram; seismic intensity; сейсмічне мікрорайонування; спектральний аналіз; методика спектральних відношень; сейсмограма; сейсмічна інтенсивність; сейсмическое микрорайонирование; спектральный анализ; методика спектральных отношений; сейсмограмма; сейсмическая интенсивность
• Online Access: https://journals.uran.ua/geofizicheskiy/article/view/210676

Seismic Microzoning Method (SMM) proposed in the article, may be used in engineering seismology for measuring intensity of seismic waves taking into account soil properties of city areas, building plots etc. This Method is based on procedures of spectrum ratio HVSR (Horizontal to Vertical Spectral Ratio-an analogue of quasi-transition function. Nogoshi & Igarashi, (1971). It was later sufficiently completed and transformed by Y. Nakamura, and obtained maximal distribution as «H/V Nakamura's ratio», and proved oneself to be good at the studies of both resonant properties of soils and dynamic characteristics of different construxtional objects. The authors of this article proposed one more application of the procedure for seismic microzoning aimed at increase of efficiency of these studies and accuracy and stability of determination of accretion of seismic intensity on the studied soils during elastic actions produced for instance by earthquakes of native or anthropogenic nature. In the area of exploration a record of micro-fluctuations is conducted with the help of three-component seismic sensors installed on the soils with different engineering-geological conditions. The obtained seismogram is subdivided into a lot of small fragments with minimum noises. The spectrum of each fragment is calculated. Then spectra of horizontal components X and Y, and vertical component Z are calculated for every small fragment. Resulting spectra of horizontals components H and spectra of vertical component V are found. After calculation of transfer function H/V, maximum of gain factor by cross-cut vibrations on the exploration area [(H/V)max]i and on the weighted average (calibration) area [(H/V)max]0 are determined. Then the increase of seismic intensity is calculated: As a result of using the novel Seismic Microzoning Method productivity of labour, accuracy and stability of calculation of ΔI is increased.