Vibroseis correlation

Seismic Data Analysis

Series	Investigations in Geophysics
Author	Öz Yilmaz
DOI	http://dx.doi.org/10.1190/1.9781560801580
ISBN	ISBN 978-1-56080-094-1
Store	SEG Online Store

Figure 1.1-20  Vibroseis correlation: the sweep signal is correlated with the recorded vibroseis record to get correlated field data. A 10-s sweep and 15-s recorded data yield a 5-s correlated record.

One other important process is the vibroseis correlation. This involves crosscorrelation of a sweep signal with the recorded vibroseis trace. The sweep is a frequency-modulated vibroseis source signal input to the ground. The convolutional model for vibroseis data is described in field data examples.

Figure 1.1-20 shows a vibroseis sweep signal, a recorded common-source gather, and the correlated gather. The sweep length is 10 s with a frequency band of 6 to 60 Hz. The 15-s uncorrelated vibroseis record yields a 5-s correlated record. Note that the early part of the uncorrelated record contains low-frequency energy with increasingly higher frequencies at late times. This is because an upsweep (frequency increasing with time) signal was used in this data example.

See also

• Analog versus digital signal
• Frequency aliasing
• Phase considerations
• Time-domain operations
• Convolution
• Crosscorrelation and autocorrelation
• Frequency filtering
• Practical aspects of frequency filtering
• Bandwidth and vertical resolution
• Time-variant filtering

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