Signal and Noise
Published:January 01, 2011
One part of the data collected by acquisition geophysicists is useful in making seismic images, and the other part can prevent those images from being useful. Sorting one part from the other is one task of the processing geophysicist. Acquisition geophysi-cists must provide conditions to make sorting feasible. In general, the conditions are met when the signal portion is large and noise is small. However, the available leverage on the respective importance of signal and noise is finite and often limited. This chapter is about the leverage and its limitations. Some essential properties of seismic body waves (signal) are reviewed in the first section. The second section is dedicated to noise. The third section discusses the relationship between the two. Often, the relationship is described by the signal-to-noise ratio (S/N). The debate on this subject is far from being closed.
Figures & Tables
Seismic Acquisition from Yesterday to Tomorrow
During the last few years, seismic acquisition has gone through a phase of fast acceleration, attested to by the development of wide-azimuth surveys, the continuous increase in channel count, and the progress in simultaneous shooting. These developments, made possible by technological advancements today, will enable the production of clearer seismic images tomorrow. Seismic Acquisition from Yesterday to Tomorrow (SEG Distinguished Instructor Series No. 14), the companion book for the 2011 SEG/EAGE Distinguished Instructor Short Course, offers a reflection on this evolution. It starts with a short historical overview, followed by discussions of signal and noise. The core of the book is the relationship between acquisition parameters and seismicimage quality. It will provide geoscientists and all those interested in seismic images with the still unconventional view of seismic data acquisition as the first component of seismic imaging.