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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>Paul A. Hsieh</dc:contributor>
  <dc:contributor>Randall A. White</dc:contributor>
  <dc:contributor>Jacob B. Lowenstern</dc:contributor>
  <dc:contributor>Steven E. Ingebritsen</dc:contributor>
  <dc:creator>Cecile A. Coulon</dc:creator>
  <dc:date>2017</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Distal volcano-tectonic (dVT) seismicity typically precedes eruption at long-dormant volcanoes by days to years. Precursory dVT seismicity may reflect magma-induced fluid-pressure pulses that intersect critically stressed faults. We explored this hypothesis using an open-source magmatic-hydrothermal code that simulates multiphase fluid and heat transport over the temperature range 0 to 1200&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;°C. We calculated fluid-pressure changes caused by a small (0.04&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;km&lt;/span&gt;&lt;sup&gt;3&lt;/sup&gt;&lt;span&gt;) intrusion and explored the effects of flow geometry (channelized vs. radial flow), magma devolatilization rates (0–15&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;kg/s), and intrusion depths (5 and 7.5&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;km, above and below the brittle-ductile transition). Magma and host-rock permeabilities were key controlling parameters and we tested a wide range of permeability (&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;) and permeability anisotropies (&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;sub&gt;h&lt;/sub&gt;&lt;span&gt;/&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;sub&gt;v&lt;/sub&gt;&lt;span&gt;), including&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;constant,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;(&lt;/span&gt;&lt;i&gt;z&lt;/i&gt;&lt;span&gt;),&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;(&lt;/span&gt;&lt;i&gt;T&lt;/i&gt;&lt;span&gt;), and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;(&lt;/span&gt;&lt;i&gt;z&lt;/i&gt;&lt;span&gt;,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;T&lt;/i&gt;&lt;span&gt;,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;P&lt;/i&gt;&lt;span&gt;) distributions, examining a total of ~&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;1600 realizations to explore the relevant parameter space. Propagation of potentially causal pressure changes (Δ&lt;/span&gt;&lt;i&gt;P&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;≥&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;0.1 bars) to the mean dVT location (6&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;km lateral distance, 6&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;km depth) was favored by channelized fluid flow, high devolatilization rates, and permeabilities similar to those found in geothermal reservoirs (&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;~&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;10&lt;/span&gt;&lt;sup&gt;−&amp;nbsp;16&lt;/sup&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to 10&lt;/span&gt;&lt;sup&gt;−&amp;nbsp;13&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;m&lt;/span&gt;&lt;sup&gt;2&lt;/sup&gt;&lt;span&gt;). For channelized flow, magma-induced thermal pressurization alone can generate cases of ∆&lt;/span&gt;&lt;i&gt;&amp;nbsp;P&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;≥&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;0.1 bars for all permeabilities in the range 10&lt;/span&gt;&lt;sup&gt;−&amp;nbsp;16&lt;/sup&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to 10&lt;/span&gt;&lt;sup&gt;−&amp;nbsp;13&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;m&lt;/span&gt;&lt;sup&gt;2&lt;/sup&gt;&lt;span&gt;, whereas in radial flow regimes thermal pressurization causes ∆&lt;/span&gt;&lt;i&gt;&amp;nbsp;P&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;&amp;lt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;0.1 bars for all permeabilities. Changes in distal fluid pressure occurred before proximal pressure changes given modest anisotropies (&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;sub&gt;h&lt;/sub&gt;&lt;span&gt;/&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;sub&gt;v&lt;/sub&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;~&lt;/span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;span&gt;10–100). Invoking&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;(&lt;/span&gt;&lt;i&gt;z&lt;/i&gt;&lt;span&gt;,&lt;/span&gt;&lt;i&gt;T&lt;/i&gt;&lt;span&gt;,&lt;/span&gt;&lt;i&gt;P&lt;/i&gt;&lt;span&gt;) and high, sustained devolatilization rates caused large dynamic fluctuations in&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;k&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;/span&gt;&lt;i&gt;P&lt;/i&gt;&lt;span&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;in the near-magma environment but had little effect on pressure changes at the distal dVT location. Intrusion below the brittle-ductile transition damps but does not prevent pressure transmission to the dVT site.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/j.jvolgeores.2017.07.011</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Causes of distal volcano-tectonic seismicity inferred from hydrothermal modeling</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>