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1

Comparison of site effect values obtained by HVSR and HVSRN methods for single-station measurements in Tarnówek, South-Western Poland

Mendecki M. J., Bieta B., Mateuszów M., Suszka P.

Contemporary Trends in Geoscience

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2016

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Vol. 5, iss. 1

18--27

EN

This study compares the HVSR technique (Horizontal to Vertical Spectral Ratio), based on seismic event records, and the HVSRN technique (Horizontal to Vertical Spectral Ratio of Noise) using seismic noise registrations. Both methods allow us to study the amplification phenomenon of a horizontal component of seismic waves when the waves reach loose sediments in subsurface layers. The seismic data were measured at a three-component single seismic station located in the village of Tarnówek, in the Legnica-Głogów Copper District. The results of the study demonstrate that average HVSRN and HVSR maxima can be distinguished: for periods approximately 3.78 s (H/V = 6.2) and 3.969 s (H/V = 8.98) respectively. The evaluated share of the Rayleigh wave component in the recorded values was β = 0.58 and it can be suggested that the Love wave share in surface motion was insignificant. The Love wave share remains unknown.

2

Determination of the resonance frequency - thickness relation based on the ambient seismic noise records from Upper Silesia Coal Basin

Mendecki M. J., Bieta B., Mycka M.

Contemporary Trends in Geoscience

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2014

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Vol. 3, iss. 1

41--51

EN

In this paper the Horizontal-to-Vertical Spectral Ratio (HVSR) method and seismic data were applied to evaluate the resonance frequency – thickness relation. The HVSR method was used to estimate the parameters of site effects: amplification and resonance frequency from seismic noise records. The seismic noise was generated by artificial source occurring in Upper Silesia Coal Basin (UBSC), Poland, such as: traffic, industry, coal plants etc. The survey points were located near the Faculty of Earth Sciences in Sosnowiec, Bytom and Chorzow. Based on Albarello’s statistical test the observed H/V maxima was confirmed or rejected. Resonance frequencies were compared with available thicknesses of soft layer obtained by seismic survey (Mendecki 2012). Finally, the estimated resonance frequency – thickness relation for UBSC area showed quite similar power function coefficients as those obtained by other authors.

3

Relacja tłumienia wartości szczytowej przyspieszenia drgań gruntu z uwzględnieniem amplifikacji dla wybranych rejonów obszaru LGOM

Olszewska D., Lasocki S.

WUG : bezpieczeństwo pracy i ochrona środowiska w górnictwie

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2006

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nr 6

19-20

PL

W oparciu o dane sejsmometryczne z 14 stanowisk znajdujących się na terenie Legnicko-Głogowskiego Okręgu Miedziowego badano tłumienie wartości szczytowej drgań gruntu w zależności od odległości od źródła, energii źródłowej i lokalnego wzmocnienia. Na podstawie przyjętego modelu wyznaczono relacje tłumienia przyspieszenia drgań gruntu składowej poziomej z uwzględnieniem amplifikacji. Przyjęty model na podstawie rejestracji ze wszystkich stanowisk pozwala na wyznaczanie współczynników reprezentujących zależność od odległości epicentralnej i energii wstrząsu oraz wyznaczenie indywidualnych współczynników opisujących lokalne wzmocnienie na każdym ze stanowisk. Tak wyznaczone względne współczynniki wzmocnienia, w odniesieniu do warunków lokalnych na jednym ze stanowisk, zostały porównane ze współczynnikami amplifikacji wyznaczonymi na podstawie metody HVSR.

EN

The data from 14 seismometer station located on Legnica-Glogow Copper District is used to study the attenuation of ground peak acceleration due to epicentre distance, source energy and site effects. The attenuation relation is estimated using the model which implicate factor of amplification. This model give opportunity to estimated factor of epicenter distance and source for all data and also estimated the individual amplification factor of each station. Those amplification factor obtained using regression model are being compeer witch amplification factor based on HVSR method.

4

Application of the horizontal to vertical spectral ratio technique for estimating the site characteristics of ground motion caused by mining induced events

Olszewska D., Lasocki S.

Acta Geophysica Polonica

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2004

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Vol. 52, nr 3

301-318

EN

The work presents an attempt of application of the horizontal-to-vertical spectral ratio (HVSR) method for estimating the local amplification of ground motion caused by mining seismic events in the Legnica Głogów Copper District. Amplifying properties of the surface layer are assessed from the ratio of amplitude spectra of the horizontal and vertical components of ground acceleration, recorded at the surface. The location of a local maximum of the ratio in the frequency band up to 8 Hz assigns the resonant frequency of the surface layer; the maximal value estimates the amplification factor at the measurement point. The spectral ratio was evaluated for 219 ground acceleration records from ten recording stations. The HVSR curves for induced seismicity turned out to be similar to the typical HVSR-s for natural earthquakes. Amplification factors estimated by the HVSR method were used to reduce the observed peak ground accelerations (PGA-s) to the bedrock. The reduction significantly improved an agreement beween the PGA values order and the order of epicentral distances. The obtained results suggest that the HVSR method can be successfully used to evaluate the local influence of the surface layer also for induced seismicity, in spite of the fact that in this case the conditions for application of the method essentially differ from the conditions met in natural seismicity.