Application of the Stockwell transform to blasting-induced ground vibration

Vibration frequency depends strongly on the propagating media and blast delay intervals. Frequency analysis is therefore important in selecting optimum blast delay intervals. The application of Fourier frequency analysis to determine the dominant frequency in ground motion is quite common. The Fourier spectra provide a complete description of the amplitudes of waveforms versus frequency, but these do not contain information regarding the time duration of these waveforms. Moreover, it is well known that damage to structures is dependent on the time duration of blasts as well as on the amplitudes and frequency of waves. Therefore, in addition to the dominant frequency of the waveform, the time duration of the waveform at that frequency must also be known. The Stockwell transform (S-transform) overcomes this difficulty in such a way that the S-transform of particle velocity records offers a means of representing the variation of spectral components with time. This paper examines the use of the S-transform fo...