Magnitudes¶
Magnitudes are computed based on amplitudes measured from waveforms. Different types of amplitudes and magnitudes are available which are listed in scamp and scmag.
Amplitudes¶
Amplitudes can be measured automatically from waveforms
During phase picking by scautopick with generally fixed time windows due to the absence of knowledge about source parameters or by,
scamp as soon as origins are available. Depending on the magnitude type, fixed or distance-dependent time windows apply.
and interactively using scolv.
Instrument simulation¶
Amplitude measurements for some magnitude types require or allow the simulation
of instruments such as Wood-Anderson torsion seismometers
(Richter [53], Uhrhammer and Collins [59]), WWSSN_SP() or WWSSN_LP().
The calibration parameters describing the Wood-Anderson seismometer are
configurable in global bindings or global module configuration:
amplitudes.WoodAnderson.gain, amplitudes.WoodAnderson.T0,
amplitudes.WoodAnderson.h. Specifically, the difference in magnitude
due to configuration using original values listed in
Richter [53] and updated ones given in Uhrhammer and Collins [59]
result in a constant offset of 0.13 in those magnitudes which apply
Wood-Anderson simulation, e.g. ML,
MLv, MLc.
Station Magnitudes¶
Station magnitudes are computed automatically by scmag or interactively by scolv from measured amplitudes based on distance-dependent calibration curves which depend on magnitude type.
Regionalization¶
The computation of station magnitudes can be regionalized. This means that for a specific region different conditions apply for computing magnitudes. The conditions include calibration curves, distance and depth ranges, etc. Regionalization is achieved by adding magnitude-type profiles in the magnitudes section of global module configuration parameters.
Network magnitudes¶
Network magnitudes are computed automatically by scmag or interactively by scolv from station magnitudes based on averaging station magnitudes. The averaging methods applied by scmag are configurable by magnitudes.average.
Summary magnitude¶
In order to account for different phenomena related to magnitude computation including magnitude saturation and application of different magnitude types at specific distance and depth ranges of the sources a summary magnitude can be computed by scmag from network magnitudes.
