Thread: sac files format

Hi, I'm trying to fully understand the header of sac files. In http://www.iris.edu./manuals/rdseed.htm#header at the Dta Recovery section they said the header is

yyyy.ddd.hh.mm.ss.ffff.SSSSS.CCC.SAC

where yyyy is the year, ddd is the Julian day, hh.mm.ss.ffff is the time of day of the start of the first record, SSSSS is the station name, and CCC is the component name for the particular seismogram being recovered, BUT I found that there are data missing: two letters before the station name which I found are the network, one letter before .SAC whith is the data quality and three letters after the name stations with I still wonder what do they mean. I want to know if this are copies one of other or something like this.
Thanks a lot
Sonia Castro


Sonia Castro Alarcón
Universidad de los Andes

UBI CARITAS ET AMOR
DEUS IBI EST