Stream Naming Conventions

The seismic, and related, data stream naming conventions are based on historical usage together with recommendations from the SEED manual. Sometimes codes were created and used were no appropriate conventions applied at the time, these were generally left as is even after later conventions were developed.

Network Code

The seismic data is expected to be globally distributed, which means the codes need to be internationally registered. The current approach is to use the already registered NZ network code for all recorded public data. Otherwise the internal XX code is used for temporary or private data that will not, or cannot, be exported.

Station Code

The National Seismograph Network station codes have, over time, developed into three letter codes with generally the last letter being a Z. The exceptions being the very oldest installations such as WEL. The trailing Z has generally made registering station codes easier.

In the past, the National Strong Motion Network recording sites tended to have a numbering system with a three digit prefix and a trailing letter. Equipment at these sites were mostly analogue, with manually digitized data. The current National Strong Motion Network site code naming convention is to use four letter codes, with all data recorded digitally.

For National Seismograph Network sites they generally follow the convention of having three letters, with a last being a Z. Other Regional Seismograph Networks use a four letter code, again with the last letter being a Z. The letter prior to this can also represent the regional or geographic network the station is in. Exceptions to this are generally the very oldest sites which pre-date the addition of the trailing Z. All other sites use four letter codes with the trailing letter giving some indication of the network or geographical location. For older sites the suffixes tend to be the initial letter of the original network code as outlined above.

For any future major instrument expansions the use of five letter station codes may be needed.

Location Code

There are two types of location codes used and are related to either sensor placement or the recording datalogger. The location code is primarily used to distinguish between multiple sensors installed at a single recording site where the same station code is used. The location code is also used to distinguish between the SOH records taken from any dataloggers which may be installed at the same site.

The SEED format requires that the location code, if used, be case independent (upper-case), and made up only of the standard letters A-Z, numbers 0-9, or the space character. There are no related SEED usage conventions although originally the global networks tended to use the location code to distinguish between sensors that were installed at various depths down boreholes from those installed on the surface.

The current convention is used to both indicate sensor type and location.

There is an informal convention of using 01 for the primary datalogger (generally weak-motion) and 02 for the secondary datalogger (generally strong motion). This setup has been maintained for sites with only strong-motion recorders as it makes maintaining instrument configurations easier.

Testing, or non-production, dataloggers will have codes using the sequence: 0Z, 0Y, 0X, ... etc. They should also use a similar sensor location sequence depending on sensor type, e.g. 1Z, 1Y, 1X ... etc.

Channel Code

Channel codes generally follow the SEED conventions, although some channel codes preceded the conventions and have not been updated.

Apart from a small number of state of health (SOH) channels, the first letter of the code represents a combination of sampling rate and sensor bandwidth, e.g.

The second letter represents the sensor type, e.g..

The third letter either represents the sensor orientation or a processing stage.

Example Channels

Data Channels

Channel Measurement
VHZ VHN VHE VH1 VH2 velocity -- broadband
LHZ LHN LHE LH1 LH2 velocity -- broadband
BHZ BHN BHE BH1 BH2 velocity -- broadband
HHZ HHN HHE HH1 HH2 velocity -- broadband
SHZ SHN SHE SH1 SH2 velocity -- short period
EHZ EHN EHE EH1 EH2 velocity -- short period
SLE SLN SLZ velocity -- low gain sensor
HNZ HNN HNE HN1 HN2 acceleration -- strong motion
BNZ BNN BNE BN1 BN2 acceleration -- strong motion
HDF BDF LDF pressure -- barometer)
HDH BDH LDH pressure -- hydrophone)
LDA HDA pressure -- microphone
VTZ LTZ BTZ pressure - water
VTH LTH BTH pressure - corrected water depth
VTT LTT BTT pressure - water depth with tide removed
LAX LAY tilt
BKO LKO VKO temperature (e.g. lake)
LKD LKS temperature (e.g. geomag sensor)
LFX LFY LFZ geomagnetic -- field values
LFF LFD geomagnetic -- full field values
CRX tidal height CREX encoded messages

Data Quality Channels

Channel Measurement
VMZ VM1 VM2 VMN VME mass position - broadband sensor offset
LMZ LM1 LM2 LMN LME mass position - broadband sensor offset
VMU VMV VMW mass position - broadband sensor offset
LMU LMV LMW mass position - broadband sensor offset
LEQ VEQ geomagnetic - absolute field observation quality
CAL sensor calibration details
BTL packet latency times

State of Health Channels

Channel Measurement
LOG General log messages in encoded text format
ACE Clock timing messages in encoded text format
UEP VEP LEP Instrument voltage
LEB Instrument internal battery voltage
VEC LEC Instrument current
UK1 UK2 Internal instrument temperatures
VKI LKI Internal instrument temperature
LII Instrument humidity
LEU Instrument CPU load
VEM LEM Instrument percent disk free or buffer full
UCQ VCQ LCQ Clock quality
LCE Clock phase error
VEA Clock antenna current
VCO Clock VCO frequency control
UCD Clock drift