Summary
This metric reports smallest amplitude value in counts encountered within a 24-hour window.
Uses
Along with the maximum value, the minimum amplitude is the time series’ most extreme value or smallest outlier. A healthy instrument recording noise will have a roughly Gaussian distribution with the minimum and maximum amplitudes being roughly symmetric about the mean and median. Departures from this could indicate less than ideal instrument behavior.
Data Analyzed
Traces – one N.S.L.C (Network.Station.Location.Channel) per measurement
Window – 24 hours starting at 00:00:00 UTC
Data Source – IRIS miniSEED archive or IRIS PH5 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.
- Identify and report the minimum amplitude value for the requested data:
For i=1,N samples in the time series x: if (x(i) < current_min) {current_min = x(i)}
Metric Values Returned
value – minimum amplitude in counts
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
Instrument response has not been removed.
