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Acta Geophysica

, Volume 66, Issue 2, pp 153–165 | Cite as

Characterization of site conditions for selected seismic stations in eastern part of Romania

  • B. Grecu
  • B. Zaharia
  • M. Diaconescu
  • A. Bala
  • E. Nastase
  • E. Constantinescu
  • D. Tataru
Research Article - Solid Earth Sciences
  • 128 Downloads

Abstract

Strong motion data are essential for seismic hazard assessment. To correctly understand and use this kind of data is necessary to have a good knowledge of local site conditions. Romania has one of the largest strong motion networks in Europe with 134 real-time stations. In this work, we aim to do a comprehensive site characterization for eight of these stations located in the eastern part of Romania. We make use of a various seismological dataset and we perform ambient noise and earthquake-based investigations to estimate the background noise level, the resonance frequencies and amplification of each site. We also derive the Vs30 parameter from the surface shear-wave velocity profiles obtained through the inversion of the Rayleigh waves recorded in active seismic measurements. Our analyses indicate similar results for seven stations: high noise levels for frequencies larger than 1 Hz, well defined fundamental resonance at low frequencies (0.15–0.29 Hz), moderate amplification levels (up to 4 units) for frequencies between 0.15 and 5–7 Hz and same soil class (type C) according to the estimated Vs30 and Eurocode 8. In contrast, the eighth station for which the soil class is evaluated of type B exhibits a very good noise level for a wide range of frequencies (0.01–20 Hz), a broader fundamental resonance at high frequencies (~ 8 Hz) and a flat amplification curve between 0.1 and 3–4 Hz.

Keywords

Ambient seismic noise Resonance frequency Soil amplification Rayleigh waves Vs30 

Notes

Acknowledgements

This work was partly supported by a grant from the Romanian National Authority for Scientific Research and Innovation (ANCSI)-UEFISCDI, project number PN-II-RU-TE-2014-4-0701 and partly by a project carried out within Nucleu Program, supported by ANCSI, project number PN 16 35 01 01. The authors express their thanks to Viorel Pirvu who helped with the active seismic measurements performed at seismic stations.

Compliance with ethical standards

Conflict of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest.

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Copyright information

© Institute of Geophysics, Polish Academy of Sciences & Polish Academy of Sciences 2018

Authors and Affiliations

  • B. Grecu
    • 1
  • B. Zaharia
    • 1
  • M. Diaconescu
    • 1
  • A. Bala
    • 1
  • E. Nastase
    • 1
  • E. Constantinescu
    • 1
  • D. Tataru
    • 1
  1. 1.National Institute for Earth PhysicsMăgureleRomania

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