ical ▁data . ▁It ▁is ▁an ▁open ▁standard , ▁and ▁is ▁controlled ▁by ▁the ▁SE G ▁Techn ical ▁Stand ards ▁Committee , ▁a ▁non - pro fit ▁organization . ▁ ▁The ▁format ▁was ▁originally ▁developed ▁in ▁ 1 9 7 3 ▁to ▁store ▁single - line ▁se ism ic ▁reflection ▁digital ▁data ▁on ▁magnetic ▁t apes . ▁The ▁specification ▁was ▁published ▁in ▁ 1 9 7 5 . ▁ ▁The ▁format ▁and ▁its ▁name ▁evol ved ▁from ▁the ▁SE G ▁" Ex " ▁or ▁Exchange ▁T ape ▁Format . ▁However , ▁since ▁its ▁release , ▁there ▁have ▁been ▁significant ▁adv anc ements ▁in ▁ge oph ys ical ▁data ▁ac quisition , ▁such ▁as ▁ 3 - dimensional ▁se ism ic ▁techniques ▁and ▁high ▁speed , ▁high ▁capacity ▁recording . ▁ ▁The ▁most ▁recent ▁revision ▁of ▁the ▁SE G - Y ▁format ▁was ▁published ▁in ▁ 2 0 1 7 , ▁named ▁the ▁rev ▁ 2 . 0 ▁specification . ▁It ▁still ▁features ▁certain ▁leg a cies ▁of ▁the ▁original ▁format ▁( re ferred ▁as ▁rev ▁ 0 ), ▁such ▁as ▁an ▁optional ▁SE G - Y ▁t ape ▁label , ▁the ▁main ▁ 3 2 0 0 ▁byte ▁text ual ▁E BC D IC ▁character ▁encoded ▁t ape ▁header ▁and ▁a ▁ 4 0 0 ▁byte ▁binary ▁header . ▁ ▁This ▁image ▁shows ▁the ▁byte ▁stream ▁structure ▁of ▁a ▁SE G - Y ▁file , ▁with ▁rev ▁ 1 ▁Ext ended ▁Text ual ▁File ▁Header ▁records . ▁ ▁Many ▁SE G - Y