SAGE Facility MUSTANG metrics Web Service Documentation

Indicates the size of the largest overlap in seconds encountered within a 24-hour window.

Data in the IRIS SEED archive is currently merged (M-quality) data, which by definition omits overlapping data. Consequently, this metric is deprecated.

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

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

• Request 24 hours of data for a single Channel (N.S.L.C).
• Request the data sample rate, defining an overlap as larger than one sample interval.
• For x data segments returned,
  • Calculate end time of each data segment:
    

    endtime(x) = starttime(x) + ( (num_samples(x) – 1) / sample_rate)
    

  • Determine the number of seconds that a previous segment overlaps the next:
    

    overlap(x) = endtime(x-1) – starttime(x)  - (1 / sample_rate)
    

  • Find the maximum overlap length for this day:
    

    max_overlap(x) = max( (overlap(x) > 0), max_overlap(x-1) )
    

value – maximum daily overlap length in seconds
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)

Overlap lengths currently are not measured across day boundaries. An overlap crossing a day boundary is treated as two separate overlaps for purposes of measuring maximum daily overlap length.