SAGE Facility MUSTANG metrics Web Service Documentation

event_begin Beginning of an event, station trigger

Summary

This metric counts the times this activity flag is set from 0 (default) to 1 in the fixed section of the miniSEED header of triggered data streams. A flag value of 1 indicates that an event trigger has taken place. Not all dataloggers set this flag.

PH5-format data does not include miniSEED flag information; this metric will always return a value of 0 for data in the IRIS PH5 archive.

Uses

This metric can be used to quickly identify data days that may have events. It may also indicate when trigger parameters need adjusting at a station.

If using this metric with the rrds service, be aware that a value of 0 (zero) can either mean that

  • the datalogger detected 0 instances of this condition,
  • the channel is not a triggered channel, or
  • the datalogger does not set this flag, so it is unknown whether or not this condition occurred.

Unless all channels in an rrds request are triggered and known to set this flag, requesting only data with a value greater than 0 will omit non-triggered channels and triggered channels for which this flag is not set.

Data Analyzed

Traces – one N.S.L.C (Network.Station.Location.Channel) per measurement
Window – 24 hours starting at 00:00:00 UTC
Data SourceIRIS miniSEED archive

SEED Channel Types – ?H?, ?L?, ?N?, ?G?, ?P?, VM? | High Gain, Low Gain, Accelerometer, Gravimeter, Geophone, Mass Channels

Algorithm

  • Request 24 hours of data for a single N.S.L.C.
  • Count and report the number times this binary flag is set to 1.

Metric Values Returned

value – number of times this flag is set to 1 that day
target – the trace analyzed, labeled as N.S.L.C.Q (Network.Station.Location.Channel.Quality)
start – beginning of the data day requested (00:00:00 UTC)
end – end of the data day requested (truncated as 23:59:59 UTC)
lddate – date/time the measurement was made and loaded into the MUSTANG database (UTC)

Notes

Not all dataloggers set this flag. For those that do not, a value of 0 does not necessarily mean that event triggers aren’t occurring.

Contact

See Also

Updated