rdseed is IRIS DMC’s legacy utility for reading SEED volumes, the FDSN-approved file format for representing and distributing digital seismic data. This utility allows the user to read the contents of the SEED file and convert it to many different output formats, extracting the data, station information, or instrument responses from the file.
rdseed reads and interprets Standard for Exchange of Earthquake Data (SEED) files. This is the format defined by the Federation of Digital Seismographic Networks (FDSN) to represent seismic data. According to the command line function option specified by the user, rdseed will read the volume and recover the volume table of contents (
-c option), the set of abbreviation dictionaries (
-a option), or station and channel information and instrument response tables (
The desired sequential volume in a file or on tape can be selected with the (
-v option). The first volume is “1”, the second “2” and so forth. Note: this option only applies to physical volumes that contain multiple logical volumes.
Additional options allow access to detailed information concerning the actual contents of the volume. The first of these options (
-t) writes out a list of data start and stop times along with the starting record sequence numbers at which those data may be found. The other option (
-l) is primarily a diagnostic tool; it writes a description of every record in the volume.
As data is extracted from the SEED volume, rdseed looks at the orientation and sensitivity of each channel to determine if the channel polarity is reversed. Refer to the description of blockettes 52 and 58 in the SEED manual for a description of reversed polarity. A negative sensitivity in blockette 58 is indicative of a reversed polarity. The user can request that reversed channels be corrected (
-z option). This correction is a simple multiplication by -1.0 to the data samples for that specific channel. The output response file information is NOT adjusted for channels where rdseed inverts the data.