DOI: https://doi.org/10.24028/gzh.0203-3100.v40i6.2018.151023

Comparison of near-surface layers spectral characteristics under the seismic stations «Trosnyk», «Uzhgorod», «Mezhgirya» calculated using finite element method and obtained experimentally

B. Ye. Kuplevskyi, T. B. Brych

Abstract


The purpose of this work was to calculate the theoretical transfer characteristics of the sedimentary layers under the seismic stations «Trosnyk», «Uzhgorod», «Mizhgirya» of the Carpathian seismic network using the Finite element method (FEM). These results are used for comparison with the dynamic parameters of near-surface layers received experimentally; for checking the conformity of investigated environment resonance properties obtained by these methods for the possibility of their application in regional seismological studies. The research was carried out by solving the direct dynamic seismic problem using the finite element method. This method of mathematical modeling allows making calculations for models that are complex in their structure. When solving the direct dynamic seismic problem using FEM, the opportunity to take into account various exchange effects inside the model does not forfeit. Also, we can calculate models with the complex geometric environment structure and various inclusions. Using the developed technique of wave field simulation by finite element method, oscillations for models of the seismic section under the «Trosnyk», «Uzhgorod» and «Mizhgirya» stations were investigated. According to the simulation results, theoretical spectral ratios for these stations were calculated. For the Seismic Station «Mizhgirya», we observe the coincidence of two interference maxima at a frequency of 4 and 10 Hz for both charts: experimental and theoretical. For the Seismic Station «Uzhgorod», the graphs obtained by the experimental and modeling method showed identical behavior throughout the frequency range. These charts provide a stable source of noise within the city. For the Seismic Station «Trosnyk» there is a discrepancy in the behavior of experimental and model charts above 6 Hz. Such results are due to the high level of groundwater under the seismic station, which was not taken into account in the creation of the model for calculating using the finite element method.

The spectral characteristics of near-surface layers under the «Trosnyk», «Uzhgorod» and «Mizhgіrya» seismic stations were calculated by the finite element method for the first time. The results of mathematical modeling were compared with experimental measurements. The knowledge about the dynamic parameters of the upper sediment layers under seismic stations, which are the largest filter of oscillation frequencies in the spectral range, will allow more accurate interpretation of registered by these stations occurrences. The calculated spectral ratios give a possibility to estimate the degree of environmental influence on stations’ seismic signals recording, which will be the largest at frequencies corresponding to the received resonance maxima and minima. These results should be taken into account when evaluating the parameters of possible seismic effects in the territory.


Keywords


modeling; finite element method; transfer characteristic; Nakamura’s technique; resonance frequency; interference

References


Azimi, Sh. A., Kalinina, A. V., Kalinin, V. V., & Pivovarov, V. L. (1967). Dynamic and kinematic features of pulses propagating in a medium with absorption and dispersion of the phase velocity. Vestnik Moskovskogo universiteta. Seriya geologicheskaya, (1), 32—36 (in Russian).

Bate, K., & Wilson, E. (1982). Numerical analysis methods and finite element method. Moscow: Stroyizdat (in Russian).

Brych, T. B. (2010). Mathematical modeling of the influence of deepening of oil and gas well on rock stress-strain state. Visnyk Lvivskoho universytetu. Seriya fizychna, (45), 135—141 (in Ukrainian).

Verbytskyy, S. T., Rozhok, N., Brych, T. B., & Kuplovskyy, B. Ye. (2011). Nakamura’s technique and finite element method in solid amplitude-frequency response investigation. Geodynamika, 11(2), 38—40 (in Ukrainian).

Gnyp, A. G. (2012). Theoretical and experimental H/V spectra for the environment under the seismic station «Mizhgirya»: Proceedings of the scientific conference «Seismological and geophysical studies in seismically active regions» (dedicated to the 80th anniversary of the birth of T. S. Verbitskyy), May 29—30, 2012, Lviv (pp. 37—40) (in Ukrainian).

Gnyp, A. R. (2016). Synthetic and experimental frequency characteristics of near-surface layers under the seismic stations Trosnik, Uzhgorod, and Mizhhirya. Geodynamika, 20(1), 144—154. https://doi.org/10.23939/jgd2016.01.144 (in Ukrainian).

Gnyp, A. R. (2015). Synthetic frequency characteristics of near-surface layers under the seismic stations Trosnyk, Uzhgorod, and Mezhgoria. Geodynamika, 19(2), 72—83. https://doi.org/10.23939/jgd2015.02.072 (in Ukrainian).

Ilyushin, A. A. (1978). Mechanics of continuum. Moscow: Moscow University Press (in Russian).

Kendzera, O. V. (2015). Seismic hazard assessment and protection against earthquakes (practical applications of developments of Subbotin Institute of Geophysics of the National Academy of Sciences of Ukraine). Visnyk Natsionalnoyi akademiyi nauk Ukrayiny, (2), 44—57. https://doi.org/10.15407/visn2015.02.044 (in Ukrainian).

Kendzera, O., & Semenova, Yu. (2010). Allowing for amplitude-frequency characteristics of the ground layer at the seismic risk microzoning of building site in Odessa. Visnyk Kyyivskoho natsionalnoho universytetu imeni Tarasa Shevchenka. Seriya Heolohiya, (2), 10—13 (in Ukrainian).

Kobranova, V. N. (1962). Physical properties of rocks (Petrophysics). V. N. Dakhnov (Ed.). Moscow: Gostoptekhizdat (in Russian).

Kuplovskyy, B. Ye. (2010). Design of wave field for complicated arranged seismic cuts. Visnyk Lvivskoho universytetu. Seriya fizychna, (45), 126—134 (in Ukrainian).

Sedov, L. I. (1984). Mechanics of continuum (Vol. 2).

Moscow: Nauka (in Russian).

Melnikov, N. V., Rzhevskiy, V. V., & Protodyakonov, M. M. (Eds.). (1975). Reference book (cadastre) of physical properties of rocks. Moscow: Nedra (in Russian).

Timoshenko, S. P., & Gudier, J. (1975). The Theory of Elasticity. Moscow: Nauka (in Russian).

Abercrombie, R. E. (1997). Near-surface attenuation and site effects from comparison of surface and deep borehole recordings. Bulletin of the Seismological Society of America, 87(3), 731—744.

Bathe, K.-J. (1982). Finite element procedures in engineering analysis. New Jersey: Prentice-Hall, Inc., Englewood Cliffs.

Haskell, N. A. (1953). The dispersion of waves in multilayered media. Bulletin of the Seismological Society of America, 43, 17—34.

Hutton, D. V. (2004). Fundamentals of Finite Element Analysis. New York: McGraw-Hill.

Langston, Ch. A., Chiu, Sh. C., Lawrence, Z., Bodin, P., & Horton, S. (2009). Array Observations of Microseismic Noise and the Nature of H/V in the Mississippi Embayment. Bulletin of the Seismological Society of America, 99(5), 2893—2911.

Nakamura, Y. (2000). Clear Identification of Fundamental Idea of Nakamura’s Technique and its Applications. https://www.iitk.ac.in/nicee/wcee/article/2656.pdf.

Nakamura, Y. A. (1989). Method for Dynamic Characteristics Estimation of Subsurface using Microtremor on the Ground Surface. Quarterly Report of RTRI, Railway Technical Research Institute (RTRI), 30(1), 25—33.

Singiresu, S. R. (2004). The Finite Element Method in Engineering. Fourth edition. Miami: Elsevier Science & Technology Books.

Starodub, G., & Gnyp, A. (1999). Models of the Earth’s Crust Structure in the East Carpathian Region determined from Inversion of Farfield P-waveforms. Acta Geophysica Polonica, 47(4), 375—400.

Steidl, J. H., Tumarkin, A. G., & Archuleta, R. J. (1996). What is a reference site? Bulletin of the Seismological Society of America, 86(6), 1733—1748.

Thomson, W. T. (1950). Transmission of elastic waves through a stratified solid medium. Journal of Applied Physics, 21(2), 89—93. https://doi.org/10.1063/1.1699629.

Zhangxin, C. (2005). Finite Element Methods and Their Applications. Berlin, Heidelgerg: Springer-Verlag.

Zienkiewicz, O. C., & Taylor, R. L. (2005). The Finite Element Method for solid and structural mechanics. Six edition (Vol. 1—3). Oxford: Elsevier Butterworth-Heinemann.




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