A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Time–Frequency Characteristics of Seismic Signal Using Stockwell Transform
Ground motions always create great interest for seismologists and engineers worldwide. For these signal, an accurate and precise analysis of non-stationary spectral variation are a longstanding problem aiming at some characteristics of signal like any underlying periodicity. Fourier transform is a conventional tool, used to study the seismic signals. In the last few years, researchers have become attentive to the limitations of the Fourier transform. It decomposes the signal into its constituent frequency components, but does not reveal, where changes in the frequency contents occur. To overcome, it joint time–frequency representations have been introduced which is a representation of both time and frequency. Some conventional method to obtain the desired time–frequency information contained in these signals are short-time Fourier transform (STFT) and Wavelet Transform. These methods show limitation in terms of resolution. The S-transform (ST) proposed by Stockwell et al. [10] is fusion of short-time Fourier transform (STFT), and Wavelet Transform. S-transform is based on a moving and scalable localizing Gaussian window. It provides frequency-dependent resolution while maintaining a direct relationship with the Fourier spectrum. In this paper, Stockwell transform (ST), STFT, and CWT-based technique for joint time–frequency representation of seismic signal has been used. Effectiveness of ST is evaluated by comparing the result of developed non-stationary synthetic signal and real-time ground motion signal of Uttarkashi earthquake (Mw = 6.8, 20 October 1991). Stockwell transform is capable for improving the resolution of non-stationary signals as well as clearly identified the spots of concentration in energy.
Time–Frequency Characteristics of Seismic Signal Using Stockwell Transform
Ground motions always create great interest for seismologists and engineers worldwide. For these signal, an accurate and precise analysis of non-stationary spectral variation are a longstanding problem aiming at some characteristics of signal like any underlying periodicity. Fourier transform is a conventional tool, used to study the seismic signals. In the last few years, researchers have become attentive to the limitations of the Fourier transform. It decomposes the signal into its constituent frequency components, but does not reveal, where changes in the frequency contents occur. To overcome, it joint time–frequency representations have been introduced which is a representation of both time and frequency. Some conventional method to obtain the desired time–frequency information contained in these signals are short-time Fourier transform (STFT) and Wavelet Transform. These methods show limitation in terms of resolution. The S-transform (ST) proposed by Stockwell et al. [10] is fusion of short-time Fourier transform (STFT), and Wavelet Transform. S-transform is based on a moving and scalable localizing Gaussian window. It provides frequency-dependent resolution while maintaining a direct relationship with the Fourier spectrum. In this paper, Stockwell transform (ST), STFT, and CWT-based technique for joint time–frequency representation of seismic signal has been used. Effectiveness of ST is evaluated by comparing the result of developed non-stationary synthetic signal and real-time ground motion signal of Uttarkashi earthquake (Mw = 6.8, 20 October 1991). Stockwell transform is capable for improving the resolution of non-stationary signals as well as clearly identified the spots of concentration in energy.
Time–Frequency Characteristics of Seismic Signal Using Stockwell Transform
Lecture Notes in Civil Engineering
Sitharam, T. G. (editor) / Kolathayar, Sreevalsa (editor) / Sharma, Mukat Lal (editor) / Devi, Gayatri (author) / Sumathi, P. (author) / Kumar, Ashvini (author)
2021-03-23
10 pages
Article/Chapter (Book)
Electronic Resource
English
Engineering Index Backfile | 1953
Engineering Index Backfile | 1953