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Seg-y picture.gif
An image of seismic line that was originally encoded in the SEG Y format.
Filename extension .sgy, .segy
Developed by SEG Technical Standards Committee
Initial release 1975; 42 years ago (1975)
Latest release
rev 1
(May 2002; 14 years ago (2002-05))
Type of format Reflection seismology data
Extended from SEG "Ex"

The SEG Y (sometimes SEG-Y) file format is one of several standards developed by the Society of Exploration Geophysicists (SEG) for storing geophysical data. It is an open standard, and is controlled by the SEG Technical Standards Committee, a non-profit organization.

The format was originally developed in 1973 to store single-line seismic reflection digital data on magnetic tapes. The specification was published in 1975.[1]

The format and its name evolved from the SEG "Ex" or Exchange Tape Format.[1][2] However, since its release, there have been significant advancements in geophysical data acquisition, such as 3-dimensional seismic techniques and high speed, high capacity recording.

The most recent revision of the SEG Y format was published in 2002, named the rev 1 specification.[3] It still features certain legacies of the original format (referred as rev 0), such as an optional SEG Y tape label, the main 3200 byte textual EBCDIC character encoded tape header and a 400 byte binary header.

SEGY file byte stream structure.svg

This image shows the byte stream structure of a SEG Y file, with rev 1 Extended Textual File Header records.

Many SEG Y programs do not totally follow the specification. For example, ODEC uses the opposite byte order and adds 320 bytes to the tail of each trace.[4]

See also[edit]


  1. ^ a b Barry, K.M.; Cavers, D.A.; Kneale, C.W. (1975). "Recommended standards for digital tape formats" (PDF). Geophysics. 40 (2): 344–352. Bibcode:1975Geop...40..344B. doi:10.1190/1.1440530. 
  2. ^ Northwood, E.J.; Weisinger, R.C.; Bradley, J.J. (1967). "Recommended standards for digital tape formats" (PDF). Geophysics. 32 (6): 1073–1084. 
  3. ^ Norris, M.W.; Faichney, A.K., eds. (2002). SEG Y rev1 Data Exchange format (PDF). Tulsa, OK: Society of Exploration Geophysicists. 
  4. ^ "SIOSEIS DISKIN Documentation". Paul Henkart. Retrieved 2009-02-09.