Magnitudes: Regionalization, Aliases, Mw

You will …

  • Regionalize magnitude

  • Create new magnitude types as aliases from other magnitudes and amplitudes.

  • Map magnitudes to the moment magnitude, Mw

Pre-requisites for this tutorial:
Afterwards/Results/Outcomes:

  • Regionalized magnitudes,

  • New magnitude types as aliases.

  • Moment magnitudes

Time range estimate:

  • 30 minutes

Regionalize Magnitudes

By regionalization, magnitudes can be computed with region-dependent properties. The procedure to set up magnitude regionalization is:

  1. Create one file which contains the polygons surrounding the regions within which magnitude parameters shall apply. The polygon files are provided in BNA or GeoJSON format and located as set out in the documentation of map layers. The file can be created from any SeisComP GUI application providing maps, e.g., scmv.

  2. For the desired magnitude type create a magnitude-type profile in global module configuration. The name of the profile matches the name of the magnitude, e.g., MLc for the MLc magnitude.

  3. Configure the magnitudes.MLc.regionFile parameter with the full path and name of the polygon file created above.

  4. Within the magnitude-type profile create one or more magnitude-region profile(s) for defining the regionalized parameters applied to the region(s). The name of a profile corresponds to the name of the polygon contained in the polygon file to which the parameters shall apply. Use world for all regions not covered by any polygon.

  5. Configure the regionalized magnitude parameters of the magnitude-region profile. Activate the enable parameter if you wish to apply this profile.

  6. Restart the data processing:

    seiscomp restart

    or execute a GUI module.

Important

  • Parameters which can be configured along with regionalization assume defaults from global binding parameters but override global bindings parameters when configured.

  • Once regionalization is active, magnitudes for events outside the defined region(s) will not be computed. For considering such events add another magnitude-region profile with the name “world”. Magnitudes for events outside any other magnitude-region profile will then be computed according to this profile.

Station corrections

Magnitude station corrections can also be applied in case of regionalization. Simply add the names of the magnitude-region profile along with the correction parameter to the original parameter in global module configuration, global.cfg, for the respective magnitude type and station. Use comma separation for multiple regions and colon for separating the region name from the value.

Example for correcting MLv computed at station GE.UGM:

module.trunk.GE.UGM.magnitudes.MLv.offset = 0.1, europe:0.2, asia:-0.1

Note

The configuration of parameters starting with module.trunk. is not supported by scconfig. All corresponding configurations must be done by directly editing the configuration file, e.g., seiscomp/etc/global.cfg.

Magnitude Aliases

New magnitude types (aliases) can be created based on existing magnitude and amplitude types but configured specifically.

The procedure to set up magnitude aliases is:

  1. Create a magnitude alias in global.cfg by configuring magnitudes.aliases. Example:

    magnitudes.aliases = MLc1:MLc:MLc

  2. Configure the alias magnitudes in either way:

    • Write bindings parameters to global module configuration or

    • Set up regionalization:

    Binding parameters in global module configuration:

    1. Read the relevant parameter names of the original magnitude from global binding, e.g., in scconfig. The names must include the full hierarchy including all sections. Example:

      magnitudes.MLc01.parametric.c1

    2. Open the module configuration file, e.g., seiscomp/etc/global.cfg in a text editor.

    3. Prepend module.trunk.global. to the parameter name and add it along with its value to the configuration file. Example:

      module.trunk.global.magnitudes.MLc01.parametric.c1 = 0.7

    4. Add the new magnitude name to the configuration of all relevant modules, e.g., scamp, scmag, scevent, scolv.

    Note

    The parameters starting with module.trunk. are not available for configuration in scconfig.

    Warning

    Binding parameters configured in global module configuration should only be considered exceptionally. These parameters will

    • Override the corresponding parameters configured by regionalization using the region world.

    • Not be written to the database and cannot be accessed by SeisComP modules running on other computers.

    Regionalization:

    • Consider the tutorial on magnitude regionalization above.

    • For the name of the new magnitude-type profile now use the alias name.

      Hint

      When adding the magnitude-region profile in scconfig, scconfig does not know about the referenced original magnitude. Therefore, not all possible configuration parameters may be listed depending on the magnitude, e.g. for MLc. For getting the full list, first create and configure a magnitude-region profile for the referenced magnitude.

      1. Close scconfig

      2. Open the configuration file global.cfg

      3. Rename the name of the referenced magnitude in the parameters to the name of the alias.

Moment Magnitudes

All magnitudes, Mx, can be mapped to a moment magnitude, Mw(Mx). The configuration procedure is:

  1. Set up a magnitude-type profile for the original magnitude type in global module configuration. Use scconfig for creating the profile.

  2. Configure the parameter MwMapping, which will become available along with the new profile, e.g., magnitudes.MLc.MwMapping. Alternatively, add the parameter to seiscomp/etc/global.cfg. The parameter is configured as a list of sample points of a piecewise linear function mapping from the original magnitude, Mx, to Mw(Mx). Example for Mw(MLc) based on MLc:

    magnitudes.MLc.MwMapping = MLc_0:Mw(MLc)_0,MLc_1:Mw(MLc)_1,...,MLc_N:Mw(MLc)_N

    Any magnitude value outside the configured range is ignored.

    Warning

    Do not map the magnitudes mB and Mwp to Mw since this is hardcoded already and done automatically by scmag.

The new moment magnitudes will be available along with the original magnitudes and can be viewed in scolv`or :ref:`scesv and considered by scmag or scevent.

In order to avoid that summary magnitudes are computed from original magnitudes and mapped Mw together and biased to both, the original magnitudes can be blocklisted in scmag (summaryMagnitude.blacklist).

Final Tests

  • Regionalization:

    1. Start scolv with the option --debug and load an event of interest

      scolv --debug

    2. Relocate the event for generating a new origin.

    3. Compute magnitudes selecting the magnitude of interest.

    4. Inspect the computed magnitudes in the Magnitude tab of scolv or read the debug output listing the considered magnitudes and stations along with the regionalized parameters.

  • Magnitude aliases:

    1. Start scolv with the option --debug and load an event of interest

      scolv --debug

    2. Relocate the event for generating a new origin.

    3. Compute magnitudes selecting the magnitude of interest including the new alias.

    4. Inspect the computed magnitudes in the Magnitude tab of scolv or read the debug output listing the considered magnitude names and aliases along with the considered parameters and their values. Example where MLc1 is derived from MLc with a modified maximum depth:

      ...
13:30:46 [debug] GE.UGM: MLc1: effective correction (no locale) = 1.00:0.00
13:30:46 [debug] Parameters for magnitude MLc1
13:30:46 [debug]   + maximum depth: 50.000 km
13:30:46 [debug]   + distance mode: hypocentral
13:30:46 [debug]   + minimum distance: -1.000 km
13:30:46 [debug]   + maximum distance: 889.561 km
...