Lab 3: Seismic Noise Attenuation

The objective of the lab session today is to remove unwanted energy which has two main categories; a) random noise or coherent energy which are the disturbance in seismic data which lack phase coherency between adjacent traces & b) coherent noise which shows consistent phase from trace to trace. Since it is impossible to remove all noise, we are trying to improve the signal-to-noise ratio (SNR) as much as possible. In short, noise can be considered as anything other than the desired signal.

Noise in seismic records is variable in both time and space. Poor seismic records = SNR ratios < 1. 

1. Load Seismic Data (Shot number 1 – 18) before gain 

Figure 1: Seismic Data Information

Figure 2: Shot number 1-18 (before gain applied)


Figure 3: Shot number 1-18 (after gain applied)


Seismic data after gain is saved as: SeismicData_B_Gain. 


2. Loading QC-ed real seismic data of shot number 10. 

Figures 5, 6 and 7 are showing the ground roll from the real time-space (t-x), frequency space (f-x), and frequency-wavenumber (f-k) domains respectively. Clearly we can see low frequency low velocity and high amplitude around the zero-offset location. 



Figure 4: Shot number 10 seismic data information

Figure 5: Shot number 10 wiggle plotting of time-space domain containing ground roll (red lines indicate ground roll noise)


Figure 6: Shot number 10 frequency space (f-k) spectra

Figure 7: Shot number 10 frequency wavenumber (f-k) spectra. (The colour bars in figure 3 and 4 indicate the magnitude values in dB)


3. Apply and display cut-off or bandpass filter


Figure 8: Display of wiggle plotting after bandpass filtering


Figure 9: Frequency space (f-x) after bandpass filtering


Figure 10: Frequency wavenumber (f-k) after bandpass filtering


Figure 11: Displaying the difference in wiggle plotting


Figure 12: Displaying the difference in f-x domain


Figure 13: Displaying the difference in f-x domain















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