Laszlo P. Keszthelyi
Jani Radebaugh
Ashley G. Davies
Elizabeth P. Turtle
Paul E. Geissler
Kenneth P. Klaasen
Julie A. Rathbun
Alfred S. McEwen
Moses P. Milazzo
2005
<p><i>Galileo</i><span>'s Solid State Imager (SSI) observed Tvashtar Catena four times between November 1999 and October 2001, providing a unique look at a distinctive high latitude volcanic complex on Io. The first observation (orbit I25, November 1999) resolved, for the first time, an active extraterrestrial fissure eruption; the brightness temperature was at least 1300 K. The second observation (orbit I27, February 2000) showed a large (</span><span class="math"><span id="MathJax-Element-1-Frame" class="MathJax_SVG" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo is="true">&#x223C;</mo><mn is="true">500</mn><mtext is="true"></mtext><msup is="true"><mtext is="true">km</mtext><mn is="true">2</mn></msup></math>"><span class="MJX_Assistive_MathML">∼500km2</span></span></span><span>) region with many, small, hot, regions of active lava. The third observation was taken in conjunction with </span><i>Cassini</i><span> imaging in December 2000 and showed a Pele-like, annular plume deposit. The </span><i>Cassini</i><span> images revealed an </span><span class="math"><span id="MathJax-Element-2-Frame" class="MathJax_SVG" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo is="true">&#x223C;</mo><mn is="true">400</mn><mtext is="true"></mtext><mtext is="true">km</mtext></math>"><span class="MJX_Assistive_MathML">∼400km</span></span></span><span> high Pele-type plume above Tvashtar Catena. The final </span><i>Galileo</i><span> SSI observation of Tvashtar (orbit I32, October 2001), revealed that obvious (to SSI) activity had ceased, although data from </span><i>Galileo</i><span>'s Near Infrared Mapping Spectrometer(NIMS) indicated that there was still significant thermal emission from the Tvashtar region. In this paper, we primarily analyze the style of eruption during orbit I27 (February 2000). Comparison with a lava flow cooling model indicates that the behavior of the Tvashtar eruption during I27 does not match that of simple advancing lava flows. Instead, it may be an active lava lake or a complex set of lava flows with episodic, overlapping eruptions. The highest reliable color temperature is </span><span class="math"><span id="MathJax-Element-3-Frame" class="MathJax_SVG" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><mo is="true">&#x223C;</mo><mn is="true">1300</mn><mtext is="true"></mtext><mtext is="true">K</mtext></math>"><span class="MJX_Assistive_MathML">∼1300K</span></span></span><span>. Although higher temperatures cannot be ruled out, they do not need to be invoked to fit the observed data. The total power output from the active lavas in February 2000 was at least </span><span class="math"><span id="MathJax-Element-4-Frame" class="MathJax_SVG" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML"><msup is="true"><mn is="true">10</mn><mn is="true">11</mn></msup><mtext is="true"></mtext><mtext is="true">W</mtext></math>"><span class="MJX_Assistive_MathML">1011W</span></span></span><span>.</span></p>
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10.1016/j.icarus.2005.05.013
en
Elsevier
Volcanic activity at Tvashtar Catena, Io
article