[Seisunix] Re: Help with fixing Trace number

Hi eloraafrin5 If you have access to the original field files (SEG-D, SEG-Y, etc), that may shed some light about the units used, where in the header to search for reliable information, etc. SU may have captured the wrong original headers, or may have been used in a wrong way, etc. As others said, the trace header values look inconsistent with each other. Likewise, if there is any paper record or spreadsheet of the field work, that may help. In any case, we had sonobuoy records here with offsets of many km. Not to mention seismological records. Otherwise, without other source of information, it becomes wild guesswork, as below. You could try to rewrite the trace headers with these values (save the original file first), then try to plot the reduced velocity seismogram, to see if it makes sense. 1) Assuming the units are in feet, the old fashioned British/Imperial System, still the American way, doesn't help much. The conversion factor to meters is ~0.3048, and this would make the first offset 34279m, down from 112464m but still large. 2) Assuming the units are centimeters (yes, once upon a time, the CGS system was popular) is better, reducing the first offset to 1124.64m. However, the units could be anything: mm, inches, yards, fathoms, furlongs, while the header values could just be dead wrong. I hope this helps, Gus Correa On Thu, Oct 27, 2022 at 1:54 PM Gary Billings <obs681(a)gmail.com> wrote: