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The SEG-Y (sometimes SEG Y or SEGY) file format is one of several data standards developed by the Society of Exploration Geophysicists (SEG) for the exchange of 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 three-dimensional seismic techniques and high-speed, high-capacity recording.

The next iteration of the SEG-Y format was published in 2002, named the rev 1 specification.[3] It featured certain legacies of the original format (referred as rev 0), such as an optional SEG-Y tape label, the main 3200 byte textual file header and a 400 byte binary file header. This was later updated in 2017 with the release of the rev 2 specification.[4]

The most recent version of SEG-Y published in 2023.[5] The rev 2.1 specification both addresses current industry data exchange needs and provides an explicit mechanism to support future expansion with both proprietary and officially adopted extensions.

This image shows the byte stream structure of a SEG-Y file, and highlights the differences between revisions 0, 1, 2, and 2.1:

SEG-Y bytestream all revisions .png

Most software 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.[6]

See also


  1. 1.0 1.1 Barry, K. M.; Cavers, D. A.; Kneale, C. W. (1975). "Recommended standards for digital tape formats". Geophysics 40 (2): 344–352. doi:10.1190/1.1440530.
  2. Northwood, E. J.; Weisinger, R. C.; Bradley, J. J. (1967). "Recommended standards for digital tape formats". Geophysics 32 (6): 1073–1084.
  3. Norris, M. W.; Faichney, A. K. (Eds.) (2002). SEG-Y rev1 Data Exchange format. Tulsa, OK: Society of Exploration Geophysicists.
  4. Hagelund, R.; Levin, S. A. (Eds.) (2017). SEG-Y revision 2.0 Data Exchange format. Tulsa, OK: Society of Exploration Geophysicists.
  5. Levin, S. A.; New, S. (Eds.) (2023). SEG-Y revision 2.1 Data Exchange format. Tulsa, OK: Society of Exploration Geophysicists.
  6. "SIOSEIS DISKIN Documentation". Paul Henkart.