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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>Peter J. Kelly</dc:contributor>
  <dc:contributor>Michael P. Doukas</dc:contributor>
  <dc:contributor>Taryn Lopez</dc:contributor>
  <dc:contributor>Melissa Pfeffer</dc:contributor>
  <dc:contributor>Robert G. McGimsey</dc:contributor>
  <dc:contributor>Christina A. Neal</dc:contributor>
  <dc:creator>Cynthia A. Werner</dc:creator>
  <dc:date>2013</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The 2009 eruption of Redoubt Volcano, Alaska was particularly well monitored for volcanic gas emissions. We report 35 airborne measurements of CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, and H&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;S emission rates that span from October 2008 to August 2010. The magmatic system degassed primarily as a closed system although minor amounts of open system degassing were observed in the 6&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;months prior to eruption on March 15, 2009 and over 1&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;year following cessation of dome extrusion. Only 14% of the total CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;was emitted prior to eruption even though high emissions rates (between 3630 and 9020&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;t/d) were observed in the final 6&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;weeks preceding the eruption. A minor amount of the total SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;was observed prior to eruption (4%), which was consistent with the low emission rates at that time (up to 180&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;t/d). The amount of the gas emitted during the explosive and dome growth period (March 15–July 1, 2009) was 59 and 66% of the total CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;and SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, respectively. Maximum emission rates were 33,110&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;t/d CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, 16,650&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;t/d SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, and 1230&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;t/d H&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;S. Post-eruptive passive degassing was responsible for 27 and 30% of the total CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;, respectively. SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;made up on average 92% of the total sulfur degassing throughout the eruption. Magmas were vapor saturated with a C- and S-rich volatile phase, and regardless of composition, the magmas appear to be buffered by a volatile composition with a molar CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;/SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;ratio of ~&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;2.4. Primary volatile contents calculated from degassing and erupted magma volumes range from 0.9 to 2.1&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;wt.% CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and 0.27–0.56&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;wt.% S; whole-rock normalized values are slightly lower (0.8–1.7&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;wt.% CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and 0.22–0.47&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;wt.% S) and are similar to what was calculated for the 1989–90 eruption of Redoubt. Such contents argue that primary arc magmas are rich in CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and S. Similar trends between volumes of estimated degassed magma and observed erupted magma during the eruptive period point to primary volatile contents of 1.25&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;wt.% CO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and 0.35&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;wt.% S. Assuming these values, up to 30% additional unerupted magma degassed in the year following final dome emplacement.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/j.jvolgeores.2012.04.012</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Degassing of CO2, SO2, and H2S associated with the 2009 eruption of Redoubt Volcano, Alaska</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>