Active Source Data Format Standards & Futures Stewart A. Levin Consulting Associate Faculty Dept. Geophysics, Stanford Univ.

Differentiation Field recording – SEG-D (E&P seismic) – SEG-2 (Engineering seismic) Exchange – SEG-Y and near variants (SU) – Sometimes SEG-2 or SAC Processing – SAC, SU, SEP, Madagascar, commercial vendors – HDF

Status Field recording – SEG-D 3.0 Very comprehensive GPS time stamps Continuous recording – SEG-2 Very flexible Limited to 2 Gb per file Microseismic community update effort(s)

Status Exchange – SEG-Y 1.0 Heavily (ab)used, some painful limitations New draft version 2.0 being circulated – supports multiple headers, long traces, header remapping, arbitrary sample interval, … – SEG-2 No current effort to overcome 2Gb, but has been done informally – Various processing formats used when standards are too limiting or too complicated

Status Processing – No formal standards, a number of de facto options SEG-Y flavors, SAC – SEG has licensed HDF for use with its formats

Encapsulation Efficiency – Large tape records – Fixed length blocking Completeness – Assemble related meta-data, e.g. navigation, observer’s notes, etc., with seismic – ZIP, tar, cpio don’t handle industry-sized seismic files

Encapsulation Efficiency – SEG-D and SEG-Y have primitive blocking scheme – RODE overly complex for this purpose Completeness – No widely accepted options – One of the reasons SEG wants to use HDF