Coherence spectra of rotational and translational components of mining induced seismic events

Abstract

Classical Russian S-5-S pendulum seismometer was modified for recording of the rotational components of ground motion. This seismometer was used for monitoring of mining induced seismic events in the Karviná region (Czech Republic). Together, three translational components of ground vibration velocity and one rotational component of ground vibration velocity around the vertical axis were recorded. Elaborated mining induced seismic events with epicentral distances up to 9 km were recorded in Doubrava locality, where the exploitation of black coal is still active. Numerical study of measured component attributes of mining induced seismic events is presented in this paper, namely squared Morlet wavelet coefficients and squared coherence spectrum between rotational and translational components. Squared Morlet wavelet coefficients enable to analyse time-and-frequency structure of elaborated signal, e.g. dynamics of the onset, evolution and disappearance of typical periods of the harmonic peaks, etc. Spectral measure of coherence was applied here for investigation of synchronization effects in 2-dimensional time series of translational and rotational components.

Long-range coherence between seismic noise properties in Japan and California before and after Tohoku mega-earthquake

“…This spectral measure was applied for investigating synchronization effects in multidimensional time series in seismology (Lyubushin 2008(Lyubushin , 2009(Lyubushin , 2010(Lyubushin , 2014a, hydrology (Lyubushin et al 2004) and climate researches (Lyubushin and Klyashtorin 2012). Here we use it in the particular case of 2-dimensional time series (Lyubushin et al 2015). In general case kðs; xÞ is constructed as the module of the product of componentby-component canonical coherences…”

Study of Site Effect at Seismic Station Located in Undermined Area of Karviná Region (Czech Republic)

“…These apparatuses provide digital records of measured signals in the frequency range of 0.5-30 Hz and sampling frequency of 100 Hz. Measurement of rotational component of vibrations, using newly developed S-5-SR sensor, was also performed in Orlová and Doubrava localities (Knejzlík et al 2012, Kaláb et al 2013, Lyubushin et al 2015. Results from seismological monitoring together with geotechnical studies are used also for evaluation of seismic loading of structures, e.g., Kaláb and Lednická (2012).…”