The Standard for the Exchange of Earthquake Data (SEED) was adopted by the FDSN in the 1987 and has served as the dominant standard for seismological research data archiving and exchange.
This specification of identifier is an expansion and enhancement of the identifiers defined in SEED version 2.4.
Changes from SEED 2.4¶
In SEED, a unique data source is identified in using network, station, location and channel codes, each of which is incorporated into the source identifer scheme described in this specification. Below is an overview of significant changes from the codes as used in SEED 2.4.
Expand maximum length of each code as follows:
network code: 2 => 8 characters
station code: 5 => 8 characters
location code: 2 => 8 characters
Subdivide the channel code into individually delimited codes, allowing expansion of each:
The channel code set becomes “band_source_subsource”, where:
Band indicates the general sampling rate and response band of the data source, same meaning as SEED.
Source is a code identifying an instrument or other data producer, called the instrument code in SEED.
Subsource is a code identifying a sub-category within the source, often the orientation, relative positon, or sensor type. Called the orientation code in SEED.
Single character versions of these individual codes are the same as SEED 2.4
Example: SEED 2.4 channel BHZ becomes B_H_Z in a source identifier.
Use of FDSN-defined codes is required (except for A and O band codes)
Allow dash “-” character (ASCII 45) in station and location codes.
Document a convention for temporary network codes: include 4 digit year identifying the start year of a deployment or experiment. As network codes are much larger than in SEED, they can be globally unique and would not need to be re-used.
Specify a Uniform Resource Identifier (URI)-like string as a “source identifier” (SID) constructed from a combination of the network, station, location and channel codes. This SID provides a convenient, flexible, single identifier for use in data formats, request mechanisms, etc. while allowing mapping back-and-forth between the SID and the separate codes as needed.
- Specific sampling rate ranges for band codes:
U: >= 0.01 to < 0.1 sps
V: >= 0.1 to < 1 sps
- Band code W added to fill the sampling rate gap between U and R:
W: >= 0.001 to < 0.01 sps
Band code J added for > 5000 sps.
Band code I added for irregular sampling.
Band code A, O deprecated.
Source codes X, Y deprecated.