Ms_20¶
Ms_20 is the surface wave magnitude measured on the vertical component at around 20 s period in accordance with the IASPEI standards.
Description¶
Amplitude¶
The Ms_20 amplitudes are calculated on vertical-component displacement seismograms corrected for the instrument response of a WWSSN_LP seismograph.
Station Magnitude¶
Ms_20 is the surface-wave magnitude at 20 s period based on the recommendations by the IASPEI magnitude working group issued on 27 March, 2013.
with
A: WWSSN_LP corrected ground displacement in nm measured on the vertical-component seismogram as the maximum absolute trace amplitude of a surface wave at periods between 18 s and 22 s,
T: period of the surface wave in seconds.
The term Ms_20 is chosen in accordance with the IASPEI standard as of 2013.
Alternatively, the term 
may be used.
- Amplitude unit in SeisComP3: nanometer (nm)
- Time window: 0 s - distance (km) / 3.5 km/s + 30 s
- Period range: 18 s - 22 s, configurable:
Ms_20.lowerPeriod,Ms_20.upperPeriod - Default distance range: 2 - 160 deg, configurable:
Ms_20.minimumDistance,Ms_20.maximumDistance - Depth range: <= 100 km, configurable:
Ms_20.maximumDepth
Network magnitude¶
By default, the trimmed mean is calculated from the station magnitudes to form the network magnitude. Outliers below the 25% and above the 75% percentiles are removed before the calculation.
Configuration¶
Adjust the configurable parameters in global bindings in the Ms_20 section.