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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Hiroyuki Kumagai</dc:contributor>
  <dc:contributor>B. Chouet</dc:contributor>
  <dc:contributor>P. Dawson</dc:contributor>
  <dc:creator>M. Nakano</dc:creator>
  <dc:date>2007</dc:date>
  <dc:description>&lt;div class=" metis-abstract"&gt;&lt;div class="article-section__content en main"&gt;&lt;p&gt;&lt;span class="paraNumber"&gt;[1]&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;We propose a method to investigate the dimensions and oscillation characteristics of the source of volcano-seismic signals based on waveform inversion for an extended source. An extended source is realized by a set of point sources distributed on a grid surrounding the centroid of the source in accordance with the source geometry and orientation. The source-time functions for all point sources are estimated simultaneously by waveform inversion carried out in the frequency domain. We apply a smoothing constraint to suppress short-scale noisy fluctuations of source-time functions between adjacent sources. The strength of the smoothing constraint we select is that which minimizes the Akaike Bayesian Information Criterion (ABIC). We perform a series of numerical tests to investigate the capability of our method to recover the dimensions of the source and reconstruct its oscillation characteristics. First, we use synthesized waveforms radiated by a kinematic source model that mimics the radiation from an oscillating crack. Our results demonstrate almost complete recovery of the input source dimensions and source-time function of each point source, but also point to a weaker resolution of the higher modes of crack oscillation. Second, we use synthetic waveforms generated by the acoustic resonance of a fluid-filled crack, and consider two sets of waveforms dominated by the modes with wavelengths 2&lt;i&gt;L&lt;/i&gt;/3 and 2&lt;i&gt;W&lt;/i&gt;/3, or&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;L&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and 2&lt;i&gt;L&lt;/i&gt;/5, where&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;W&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;L&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;are the crack width and length, respectively. Results from these tests indicate that the oscillating signature of the 2&lt;i&gt;L&lt;/i&gt;/3 and 2&lt;i&gt;W&lt;/i&gt;/3 modes are successfully reconstructed. The oscillating signature of the&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;L&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;mode is also well recovered, in contrast to results obtained for a point source for which the moment tensor description is inadequate. However, the oscillating signature of the 2&lt;i&gt;L&lt;/i&gt;/5 mode is poorly recovered owing to weaker resolution of short-scale crack wall motions. The triggering excitations of the oscillating cracks are successfully reconstructed.&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1029/2006JB004490</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Geophysical Union</dc:publisher>
  <dc:title>Waveform inversion of volcano-seismic signals for an extended source</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>