Ground roll attenuation using the S and x‐f‐k transforms

Abstract

Ground roll, which is characterized by low frequency and high amplitude, is an old seismic data processing problem in land‐based seismic acquisition. Common techniques for ground roll attenuation are frequency filtering, f‐k or velocity filtering and a type of f‐k filtering based on the time‐offset windowed Fourier transform. These techniques assume that the seismic signal is stationary. In this study we utilized the S, x‐f‐k and t‐f‐k transforms as alternative methods to the Fourier transform. The S transform is a type of time‐frequency transform that provides frequency‐dependent resolution while maintaining a direct relationship with the Fourier spectrum. Application of a filter based on the S transform to land seismic shot records attenuates ground roll in a time‐frequency domain. The t‐f‐k and x‐f‐k transforms are approaches to localize the apparent velocity panel of a seismic record in time and offset domains, respectively. These transforms provide a convenient way to define offset or time‐varying reject zones on the separate f‐k panel at different offsets or times.

Seismic data analysis using local time‐frequency decomposition

“…In a somewhat different approach, Liu et al (2009) minimized the error between the input signal and each frequency component independently. Askari and Siahkoohi (2008) proposed t-f -k and x-f -k transforms that are based on the S transform. In the case of nonstationarity, their approach does not guarantee invertability, because it processes each frequency independently.…”

Data adaptive ground-roll attenuation via sparsity promotion

“…An approach to address this problem is to utilize the time-frequency properties of time-frequency transforms. Such methods analyze and filter ground-roll in time-frequency domain by using timefrequency transforms such as wavelet transform (Deighan and Watts, 1997;Zhang and Ulrych, 2003), S transform (Askari and Siahkoohi, 2008), or the t-f-k and x-f-k transforms (Askari and Siahkoohi, 2008;Liu and Fomel, 2010;Zhang et al, 2010). However, during these filterings, the suppression of reflections also occurs whenever time-frequency zones containing both ground-roll and reflection amplitudes are decreased or muted from seismic data.…”

Analysis of non-stationary structural systems by using a band-variable filter

“…Taking advantage of these properties, the S-Transform has been used up to now in seismology and earthquake engineering to clean signals from unwanted noise. Examples of the use of S-Transform to enhance the signal to noise ratio are given in Pinnegar and Eaton (2003), Schimmel and Gallart (2005), Askari and Siahkoohi (2007), Simon et al (2007), Parolai (2009) and Ditommaso et al (2010a). The main goal of this paper is to provide a band-variable filter able to extract from a non-stationary signal only the phase of interest.…”