Thread: Fwd: segy2sac

On Jul 21, 2016, at 14:01, George Helffrich <George.Helffrich<at>bristol.ac.uk> wrote:

Dear Milton -

segy2sac may be platform dependent, but the SEG-Y standard is not. To quote from the standard (Norris, M. W., Faichney, A. K., eds. (2002). "SEG Y rev 1 Data Exchange
format", Society of Exploration Geophysics)”

3.3. Number Formats

In the 1975 SEG Y standard, all binary values are defined as using “big-endian” byte ordering. This conformed to the IBM tape standard and means that, within the bytes that make up a number, the most significant byte (containing the sign bit) is written closest to the beginning of the file and the least significant byte is written closest to the end of the file. This byte ordering convention is maintained in this revision of the SEG Y format and it should be adhered to for all conforming versions of SEG Y. This is independent of the medium to which a particular SEG Y file is written (i.e. the byte ordering is no different if the file is written to tape on a mainframe or to disk on a PC).

The one file that I examined (I assume the others were the same) was written in little-endian format, in other words, in contravention of the standard. Hence the files are not SEG-Y.

On 21 Jul 2016, at 20:16, Milton Plasencia <mplasencia<at>inogs.it <mplasencia<at>inogs.it>> wrote:

Abhash,

SEG-Y is platform dependent, so in my linux box (CentOS x86_64) i convert your files without problem.

milton@pcasain7:~/Temp$ segy2sac -d SAC s0001f001*
segy2sac: Version Number 2002.059

converting s0001f0010 ==> SAC/s0001f0010.sac
converting s0001f0011 ==> SAC/s0001f0011.sac
converting s0001f0012 ==> SAC/s0001f0012.sac

HTH,

Milton



* * * * * * * * * * * * * * * * * * * * * * *
Milton P. PLASENCIA LINARES

Centro di Ricerche Sismologiche (CRS)
OGS - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale

Borgo Grotta Gigante 42/C
(34010) Sgonico - Trieste - Italia
Tel: +39 040 2140 156 (Udine)
Tel: +39 040 2140 256 (Trieste)
Cel.: +39 331 6481 935

E-mail: mplasencia<at>inogs.it <mplasencia<at>inogs.it>
GPG key: 22FCFFA8

ASAIN (Antarctic Seismographic Argentinean Italian Network)
*********************************

On Jul 19, 2016, at 22:16, Abhash Kumar <abhash.kumar84<at>gmail.com <abhash.kumar84<at>gmail.com>> wrote:


Hi,
I am using "segy2sac" to convert SEG-Y files into SAC format and check the header information. I am successfully able to convert first 9 files from the SEG-Y directory into SAC format using following syntax:

segy2sac -d SAC -g segy_file

When I try to convert other files from the SEG-Y directory, I get an error of "Abort trap: 6". I looked online to find help for this error and it seems to be related to memory issue. I have enough memory and administrative right to the working directory. I have attached few example files for which segy2sac does not work on my computer. Can someone try segy2sac on the attached files. I would be extremely grateful for any suggestion to resolve this issue.

Best regards
Abhash Kumar

<s0001f0010><s0001f0011><s0001f0012>
----------------------
SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)

Sent via IRIS Message Center (http://ds.iris.edu/message-center/)
Update subscription preferences at http://ds.iris.edu/account/profile/

----------------------
SAC Help (http://ds.iris.edu/message-center/topic/sac-help/)

Sent via IRIS Message Center (http://ds.iris.edu/message-center/)
Update subscription preferences at http://ds.iris.edu/account/profile/

George Helffrich
george.helffrich<at>bris.ac.uk <george.helffrich<at>bris.ac.uk>