Thread: Fwd: SEGY 2 SAC

Started: 2012-07-05 14:00:45
Last activity: 2012-07-05 14:00:45
Topics: SAC Help
Milton Plasencia
2012-07-05 14:00:45

Begin forwarded message:

From: Milton Plasencia <mplasencia<at>>
Subject: Re: [SAC-HELP] SEGY 2 SAC
Date: July 5, 2012 6:54:06 AM GMT+02:00
To: gllore<at>
Cc: sac-help<at>

Hi Lorenzo,

The segy files are platform dependent, so yuo must do:

1) run the segyhdr command included in the PASSCAL distribution.

macton:TdF milton$ segyhdr
segyhdr: Version no. 2006.312 HEADER VALUES

Byte order is from a Sun <--------------
lineSeq ==> 1961
reelSeq ==> 1961

The output continues and you can see (line indicate by arrow) that in this case
the file is Byte order SUN, so for converting this into your Linux box
you must running the segysun2pc (another PASSCAL command)

after the "conversion" to the byte order "PC" you can running segy2sac and
read your file into SAC.

HTH, Cheers,


* * * * * * * * * * * * * * * * * * * * * * *

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

Borgo Grotta Gigante 42/C
(34010) Sgonico - TRIESTE - ITALIA
Tel: +39 040 2140 136 (Udine)
Tel: +39 040 2140 365 / 256 (Trieste)
Fax: +39-040-327307

E-mail: mplasencia<at>

ASAIN (Antarctic Seismographic Argentinean Italian Network)

On Jul 5, 2012, at 6:27 AM, Juan M Lorenzo wrote:

Dear All:

I am running the latest passoft rpm on a 64-bit RHEL6 system.

(I start with SU data and convert it to SEGY data)

I am trying to convert segy data into sac format. (The segy data can be read by pql)

I then run sierra2segy -g followed by segy2sac.

Although I get no error messages, the output from sierra2segy only generates files that are 240 bytes long,
which I can not read with pql. The segy2sac produces no output.

I am guessing my issues arise from the segy binary header (400 byte) that may be lacking an important
header value.

Does anyone have a small segy file they have converted successfully into sac? If so
I could compare what is missing in my file and perhaps discover the cause of my problem.

I would appreciate any other suggestions you may have.

Thanks for your time and advice in advance.

Juan Lorenzo

Juan M. Lorenzo
Associate Professor
Dept. Geology and Geophysics
Howe-Russell Building Room E235
Corner South Campus/Tower Drives
Louisiana State University
Baton Rouge, LA 70803-4101
Tel.: (225) 578-4249
Fax: (225) 578-2302
Seismic Shop: (225) 578-3424
Computer Lab: (225) 578-4816
e-mail: gllore<at>

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