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Ambient noise investigation of rock structures in Bohemian Paradise
Müller, Jozef
We carry out non-invasive ambient noise investigation of rock structures in Bohemian Paradise (Bohemian Cretaceous Basin, Czech Republic). The study is focused on two key topics: 1) An in-situ elastic moduli estimate of competent, horizontally deposited sandstone layers. This is done by performing an ambient noise array measurement. The recording is processed with f-k array analysis, from which frequency-dependent Love and Rayleigh wave dispersion curves as well as the Rayleigh wave ellipticity are retrieved. The data are inverted for P- and S-wave velocity profiles, from which the Young's and shear modulus are successfully estimated. 2) Study of local response of Kapelník rock tower. We analyse a dataset of ambient noise recordings from the top of the tower and from its foot. Information about tower oscillation frequencies and directions, together with amplification ratios, are retrieved from particle motion polarisation analysis and from site-to-reference spectral ratios. The Euler-Bernoulli beam theory is finally used to interpret the measured data using the elastic moduli estimated from the noise array measurement. Keywords: Bohemian Paradise, rock tower, seismic ambient noise, seismic surface waves
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Ambient noise investigation of rock structures in Bohemian Paradise
Müller, Jozef ; Burjánek, Jan (advisor) ; Zábranová, Eliška (referee)
We carry out non-invasive ambient noise investigation of rock structures in Bohemian Paradise (Bohemian Cretaceous Basin, Czech Republic). The study is focused on two key topics: 1) An in-situ elastic moduli estimate of competent, horizontally deposited sandstone layers. This is done by performing an ambient noise array measurement. The recording is processed with f-k array analysis, from which frequency-dependent Love and Rayleigh wave dispersion curves as well as the Rayleigh wave ellipticity are retrieved. The data are inverted for P- and S-wave velocity profiles, from which the Young's and shear modulus are successfully estimated. 2) Study of local response of Kapelník rock tower. We analyse a dataset of ambient noise recordings from the top of the tower and from its foot. Information about tower oscillation frequencies and directions, together with amplification ratios, are retrieved from particle motion polarisation analysis and from site-to-reference spectral ratios. The Euler-Bernoulli beam theory is finally used to interpret the measured data using the elastic moduli estimated from the noise array measurement. Keywords: Bohemian Paradise, rock tower, seismic ambient noise, seismic surface waves
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Focal mechanisms of earthquakes in the secondary focal zones in West Bohemia
Müller, Jozef ; Bachura, Martin (advisor) ; Adamová, Petra (referee)
Recent research on earthquake swarms in West Bohemia (Czechia) has been focused on the Novy Kostel Focal Zone, where, during the last decades, majority of the earthquake swarms has been observed. In this work we focus on earthquake activity surrounding this fault zone. To this purpose we estimated focal mechanisms from P-wave of earthquakes located to the west of the Novy Kostel Focal Zone, using the FOCMEC software. Dozens of earthquakes have been analysed, of which 20 produced reliable focal mechanisms (with at least 8 favourably positioned stations used). The resulting mechanisms revealed dominance of horizontal movements, which agreed well with fault orientations mapped by earthquake relocations. Results also imply the existence of normal faulting in the studied region.
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