209 lines
9.7 KiB
HTML
209 lines
9.7 KiB
HTML
<!DOCTYPE html>
|
||
|
||
<html lang="en">
|
||
<head>
|
||
<meta charset="utf-8" /><meta name="viewport" content="width=device-width, initial-scale=1" />
|
||
|
||
<title>Md — SeisComP Release documentation</title>
|
||
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
|
||
<link rel="stylesheet" href="../_static/seiscomp.css" type="text/css" />
|
||
<link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=72bcf2f2" />
|
||
<link rel="stylesheet" type="text/css" href="../_static/seiscomp.css?v=c6da7ce6" />
|
||
<link rel="stylesheet" type="text/css" href="../_static/graphviz.css?v=eafc0fe6" />
|
||
<script type="text/javascript" src="../_static/seiscomp.js"></script>
|
||
<script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
|
||
<script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js?v=823bb831"></script>
|
||
<script src="../_static/doctools.js?v=888ff710"></script>
|
||
<script src="../_static/sphinx_highlight.js?v=4825356b"></script>
|
||
<link rel="index" title="Index" href="../genindex.html" />
|
||
<link rel="search" title="Search" href="../search.html" />
|
||
<link rel="next" title="NonLinLoc" href="global_nonlinloc.html" />
|
||
<link rel="prev" title="Hypo71" href="global_hypo71.html" />
|
||
</head>
|
||
<body>
|
||
<div class="header">
|
||
<div class="container">
|
||
<div class="brand">
|
||
<img class="logo" src="../_static/brands/seiscomp/text/white.svg"/>
|
||
<!-- span class="title">SeisComP Release</span -->
|
||
<span class="version">6.9.1</span>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="nav">
|
||
<div class="container">
|
||
<div class="content"><a class="pull-right" id="sidebar-toggle">TOC</a>
|
||
|
||
<div class="related" role="navigation" aria-label="related navigation">
|
||
<ul>
|
||
<li class="right">
|
||
<a href="../genindex.html" title="General Index"
|
||
accesskey="I">
|
||
index
|
||
</a>
|
||
</li>
|
||
<li class="right">
|
||
<a href="global_nonlinloc.html" title="NonLinLoc"
|
||
accesskey="N">
|
||
next
|
||
</a>
|
||
</li>
|
||
<li class="right">
|
||
<a href="global_hypo71.html" title="Hypo71"
|
||
accesskey="P">
|
||
previous
|
||
</a>
|
||
</li>
|
||
<li class="nav-item nav-item-0">
|
||
<a href="../index.html">Home</a>
|
||
</li>
|
||
<li class="nav-item nav-item-1">
|
||
<a href="../toc/extensions.html" >Extensions</a>
|
||
</li>
|
||
<li class="nav-item nav-item-2">
|
||
<a href="../toc/extensions/global.html" accesskey="U">global</a>
|
||
</li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="container">
|
||
<div class="fitted content" id="anchors-container">
|
||
<div class="body" role="main">
|
||
|
||
<section id="md">
|
||
<span id="global-md"></span><h1>Md<a class="headerlink" href="#md" title="Permalink to this heading">¶</a></h1>
|
||
<p>Duration magnitude plugin</p>
|
||
<section id="description">
|
||
<h2>Description<a class="headerlink" href="#description" title="Permalink to this heading">¶</a></h2>
|
||
<p>The duration magnitude is based on coda duration measurement.
|
||
It’s usually valid for small earthquakes up to magnitude 4 to 5.</p>
|
||
<p>First used in 1972 by Lee et al., Duration magnitude (Md) or Coda duration
|
||
magnitude plugin estimates Richter magnitude of local earthquakes by using
|
||
signal duration on vertical components of seismographs.</p>
|
||
<p>Estimations are quite stable for local earthquakes ranging from magnitude
|
||
Md 0.0 to 5.0.</p>
|
||
<section id="amplitude-processing">
|
||
<h3>Amplitude processing<a class="headerlink" href="#amplitude-processing" title="Permalink to this heading">¶</a></h3>
|
||
<p>Duration magnitude is usually computed on short period seismometers by searching
|
||
the time at which the amplitude of the signal is close to pre-earthquake amplitude.</p>
|
||
<p>Since it’s mainly used for small earthquake whose signal is at rather high frequency,
|
||
it’s usefull to highpass filter broadband seismomters (select sismo type 6 and a
|
||
Butterworth filter “3,1.5”).
|
||
Or a better solution is to deconvolve the signals and reconvolve with a widely used
|
||
short-period instrument : the 1Hz eigen-frequency L4C (select sismo type 9).
|
||
If you have the full responses in your inventory and have activated them
|
||
(amplitudes.enableResponses set to true), you will be able to use also accelerometers.</p>
|
||
<p>The plugin then searches for the maximum amplitude of the signal, which should be
|
||
the S-wave and then computed mean amplitude of one-second time windows.
|
||
As soon as a one-second time window mean amplitude vs pre-earthquake amplitude
|
||
reaches the configured SNR ratio, the process is stopped.
|
||
The middle of the one-second time window is assumed to be the end of the Coda and
|
||
the time difference between Coda time and P arrival time is stored as Coda duration.</p>
|
||
</section>
|
||
<section id="magnitude-processing">
|
||
<h3>Magnitude processing<a class="headerlink" href="#magnitude-processing" title="Permalink to this heading">¶</a></h3>
|
||
<p>Once amplitudes calculated by the AmplitudeProcessor and a Coda has been found,
|
||
the generic formula is applied and the duration magnitude is computed
|
||
for a given station, if it fits the criteria (max depth, max distance).</p>
|
||
<div class="math">
|
||
<p><img src="../_images/math/a3010f147479b84f14b15be9438d4940ab36bca0.png" alt="mag = FMA + FMB \times \log10(period) + (FMF \times period) + (FMD \times epidistkm) + (FMZ \times depth) + STACOR"/></p>
|
||
</div></section>
|
||
</section>
|
||
<section id="plugin">
|
||
<h2>Plugin<a class="headerlink" href="#plugin" title="Permalink to this heading">¶</a></h2>
|
||
<p>The Coda duration magnitude plugin (Md) is installed under <code class="file docutils literal notranslate"><span class="pre">share/plugins/md.so</span></code>.
|
||
It provides a new implementations of AmplitudeProcessor and MagnitudeProcessor.</p>
|
||
<p>To add the plugin to a module add it to the modules configuration, either
|
||
<code class="file docutils literal notranslate"><span class="pre">modulename.cfg</span></code> or <code class="file docutils literal notranslate"><span class="pre">global.cfg</span></code>:</p>
|
||
<div class="highlight-sh notranslate"><div class="highlight"><pre><span></span><span class="nv">plugins</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="si">${</span><span class="nv">plugins</span><span class="si">}</span>,<span class="w"> </span>md
|
||
</pre></div>
|
||
</div>
|
||
<p>Basically it can be used by modules: <a class="reference internal" href="scamp.html#scamp"><span class="std std-ref">scamp</span></a>, <a class="reference internal" href="scmag.html#scmag"><span class="std std-ref">scmag</span></a>, <a class="reference internal" href="scolv.html#scolv"><span class="std std-ref">scolv</span></a>.</p>
|
||
<section id="more-information">
|
||
<h3>More information<a class="headerlink" href="#more-information" title="Permalink to this heading">¶</a></h3>
|
||
<p>Description of the formula can be found in Hypo2000 manual from USGS website.
|
||
<a class="reference external" href="http://earthquake.usgs.gov/research/software/#HYPOINVERSE">http://earthquake.usgs.gov/research/software/#HYPOINVERSE</a></p>
|
||
</section>
|
||
</section>
|
||
</section>
|
||
|
||
|
||
<div id="anchors-bottom"></div>
|
||
</div>
|
||
|
||
<div class="sidebar" role="navigation" aria-label="main navigation">
|
||
<div id="anchors-top"></div>
|
||
<div id="anchors" class="content">
|
||
<div id="searchbox" style="display: none" role="search">
|
||
<h3 id="searchlabel">Quick search</h3>
|
||
<div class="searchformwrapper">
|
||
<form class="search" action="../search.html" method="get">
|
||
<input type="text" name="q" aria-labelledby="searchlabel" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false"/>
|
||
<input type="submit" value="Go" />
|
||
</form>
|
||
</div>
|
||
</div>
|
||
<script>document.getElementById('searchbox').style.display = "block"</script>
|
||
<div>
|
||
<h3><a href="../index.html">Table of Contents</a></h3>
|
||
<ul>
|
||
<li><a class="reference internal" href="#">Md</a><ul>
|
||
<li><a class="reference internal" href="#description">Description</a><ul>
|
||
<li><a class="reference internal" href="#amplitude-processing">Amplitude processing</a></li>
|
||
<li><a class="reference internal" href="#magnitude-processing">Magnitude processing</a></li>
|
||
</ul>
|
||
</li>
|
||
<li><a class="reference internal" href="#plugin">Plugin</a><ul>
|
||
<li><a class="reference internal" href="#more-information">More information</a></li>
|
||
</ul>
|
||
</li>
|
||
</ul>
|
||
</li>
|
||
</ul>
|
||
|
||
</div>
|
||
<div>
|
||
<h4>Previous topic</h4>
|
||
<p class="topless"><a href="global_hypo71.html"
|
||
title="previous chapter">Hypo71</a></p>
|
||
</div>
|
||
<div>
|
||
<h4>Next topic</h4>
|
||
<p class="topless"><a href="global_nonlinloc.html"
|
||
title="next chapter">NonLinLoc</a></p>
|
||
</div>
|
||
<div role="note" aria-label="source link">
|
||
<h3>This Page</h3>
|
||
<ul class="this-page-menu">
|
||
<li><a href="../_sources/apps/global_md.rst.txt"
|
||
rel="nofollow">Show Source</a></li>
|
||
</ul>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<div class="footer">
|
||
<div class="container">
|
||
<div class="horizontal layout content">
|
||
<a class="fade-in" href="https://www.gempa.de" target="_blank">
|
||
<img class="brand" src="../_static/brands/gempa.svg"/>
|
||
</a>
|
||
<div class="stretched align-center fitted content">
|
||
<div>
|
||
Version <b>6.9.1</b> Release
|
||
</div>
|
||
<div class="copyright">
|
||
Copyright © gempa GmbH, GFZ Potsdam.
|
||
</div>
|
||
</div>
|
||
<a class="fade-in" href="https://www.gfz-potsdam.de" target="_blank">
|
||
<img class="brand" src="../_static/brands/gfz.svg"/>
|
||
</a>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</body>
|
||
</html> |