[seiscomp, scanloc] Install, add .gitignore

share/doc/seiscomp/html/_sources/apps/global_mb.rst.txt

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+.. _global_mb:
+
+##
+mb
+##
+
+Body wave magnitude at teleseismic distances
+
+Description
+===========
+
+mb is the standard body-wave magnitude.
+Compare also with the :ref:`mB magnitude <global_mb_bb>`.
+
+
+Amplitude
+---------
+
+mb is defined on the amplitude of the first few cycles of the P-wave,
+typically a time window of 20 s - 30 s. Only the first few cycles are used to
+minimize the effects of radiation pattern and depth phases, which result in
+complicate waveform signatures.
+In |scname| mb amplitudes are measured on vertical-component displacement seismograms
+in a 30 s time window after simulation of a :term:`WWSSN_SP` short-period
+seismometer. Amplitudes are used from stations with epicentral distances between
+5° and 105° (configurable). The methods for measuring amplitudes are configurable
+in the global bindings.
+
+
+Station Magnitude
+-----------------
+
+The general formula is
+
+.. math::
+
+   mb = \log \left(\frac{A}{T}\right) + Q(h,\Delta) - 3.0
+
+with A as the displacement amplitude in micrometers, T as the dominant period of
+the signal in seconds, Q as a correction term for depth and distance. mb is
+usually determined at periods around 1s in adaptation to the use
+of the World-Wide Standard Seismograph Network (WWSSN) short-period stations.
+A scatter in the order of +/- 0.3 for the station magnitudes is usual.
+Typically, mb is determined for stations with distances larger than 5° to
+have a distinct direct P-wave phase. A correction term for the distance has to
+be determined empirically, which is quite complicate for distances smaller than 20°.
+This reflects the complexity of the body waves that traverse only in the upper
+mantle. mb saturates at about magnitude 5.5 to 6.0 because the maximum amplitudes of larger
+earthquakes occur at lower frequencies than the frequency range between 0.7 Hz - 2 Hz
+used for the magnitude calculation.
+
+* Amplitude unit in |scname|: **nanometers** (nm)
+* Time window: 30 s
+* Default distance range: 5 - 105 deg, configurable: :confval:`magnitudes.mb.minDist`,
+  :confval:`magnitudes.mb.maxDist`
+* Depth range: no limitation, for depth < 0 km, depth = 0 km is assumed
+
+.. note::
+
+   In 2013 the IASPEI commission (:cite:t:`iaspei-2013`) recommended a minimum distance of
+   20 deg. However, :ref:`scautoloc` requires mb amplitudes by default for
+   considering a pick.
+   For maintaining consistency, 5 deg is therefore kept as the default
+   for :confval:`magnitudes.mb.minDist`.
+
+
+Network magnitude
+-----------------
+
+By default, the trimmed mean is calculated from the station magnitudes to form
+the :term:`network magnitude`. Outliers beyond the outer 12.5% percentiles are
+removed before forming the mean.
+
+
+Configuration
+-------------
+
+Adjust the configurable parameters in global bindings in the mB section or use
+:file:`global.cfg`
+as in :ref:`global_mlv`. Add mb to the list of computed amplitudes and magnitudes
+in the configuration of
+:ref:`scamp` and :ref:`scmag` and in :ref:`scesv` or :ref:`scolv`/:ref:`scesv`
+for visibility.