DBPapers
DOI: 10.5593/SGEM2015/B13/S5.106

ELABORATION OF GROUND MOTION DIRECTIVITY IN UNDERMINED AREA BASED ON SEISMIC NOISE MEASUREMENT

M. Lednicka
Friday 7 August 2015 by Libadmin2015

References: 15th International Multidisciplinary Scientific GeoConference SGEM 2015, www.sgem.org, SGEM2015 Conference Proceedings, ISBN 978-619-7105-33-9 / ISSN 1314-2704, June 18-24, 2015, Book1 Vol. 3, 815-822 pp

ABSTRACT
This paper presents azimuthal variations of noise spectral ratios determined in undermined locality of Stonava (Czech Republic). It was documented based on previous studies at this locality that there exists site effect due to the local geological pattern. The resonant frequencies calculated from the seismic records at permanent seismic stations and the resonant frequencies obtained by analysis of seismic noise measurements are represented by the spectral ratio peak of about 1 - 2 Hz. The vibration effect on the surface is in frequency and amplitude domain mainly affected by the physical and mechanical properties of sedimentary layers and underlying bedrock. Moreover, tectonic pattern and terrain morphology may affect the vibration effect on the surface by directional variations. The locality under study is a typical example of undermined area with local changes of geological pattern, different depth of groundwater level, developing subsidence depressions and complex fault system. The azimuthal variations of noise spectral ratios were determined based on seismic noise measurements at different places at the locality and results were compared with the above mentioned aspects that may influence the directivity phenomenon.

Keywords: HVNR method, undermined area, site effect, seismic noise, directivity