Loki Patera, Io

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alexblackwell

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Iophiles should like this one. There are two new papers out. <br /><br />The first is by Matson <i>et al</i>., which was published online today in the <i>Journal of Geophysical Research-Planets</i>. For those without access to <i>JGR-Planets</i>, this subject has been covered at previous LPSCs. For example, see this abstract and this one.<br /><br />Rathbun and Spencer have another paper, entitled "Loki, Io: New ground-based observations and a model describing the change from periodic overturn," which is coming out next week in <i>Geophysical Research Letters</i>. For non-GRLers, there's a preprint for this one on the LANL arXiv preprint server.
 
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3488

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Thank you very much.<br /><br />I am trying to convince NASA to send an Io Orbiter & Lander.<br /><br />Also I was successful in getting extended Io observations during the upcoming New Horizons Jupiter encounter next February, particularly images of the Jupiter facing hemisphere (very well seen by Voyager1, but poorly seen by Galileo, as the Galileo orbiter concentrated on the Io 'farside').<br /><br />I am a real Iophile.<br /><br />Andrew Brown.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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jmilsom

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Fascinating abstracts. Which of the three scenarios do you think most plausible for Loki Patera? Isolated puddle cooling monotonically, steady-state solid-liquid convection or direct heating from tidal energy with active circulation at the surface and little at depth? Or perhaps none of the above? <div class="Discussion_UserSignature"> </div>
 
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3488

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Hi jmilsom,<br /><br />I think your second theory is the correct one. I think that both Loki & Tupan Pateras sit above hot spots generated within Io's mantle. The lava lakes are just 'wounds' in the thin crust.<br /><br />I might be wrong, but I think it is deep seated hot spot volcanism. <br /><br />The magma from the mantle does not come all the way up, but burns a hole under the crust, where as lower temperature melting can occur in a sulphur rich lava lake(a little like Yellowstone in Wyoming, USA, in principle).<br /><br />It is a shame that Galileo could only return low resolution images of Loki (which is located on the Jupiter facing hemisphere). <br /><br />I believe that good IR readings where taken, which showed Loki to be although hot, not hot enough to be a true silicate lava lake (although Io does have the hottest known volcanic eruptions in the solar system, Prometheus being one). <br /><br />The close pass over Loki was ruined during a safing event & the I33 encounter which would had allowed another chance at decent Jupiter facing hemisphere imagery (as well as close up images of Amalthea during A34), did not obtain images to 'save money'.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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3488

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Tupan Patera.<br /><br />Wonderful colors in a volcanic crater named Tupan Patera on Jupiter's moon Io, as seen in this image from NASA's Galileo spacecraft, show varied results of lava interacting with sulfur-rich materials.<br /><br />The colorfulness of the image is only slightly enhanced from what the human eye would see on the scene. The red in the image includes a small amount of infrared energy. Tupan Patera, named after a Brazilian thunder god, was seen as an active hot spot in earlier Galileo observations, but those low-resolution views did not show details of volcanic activity. This image taken in October 2001 at a resolution of 135 meters (443 feet) per picture element reveals the complex nature of the crater.<br /><br />Tupan is now clearly shown to be a volcanic depression, about 75 kilometers (47 miles) across, surrounded by cliffs about 900 meters (3000 feet) tall. In the center is a large area that must be higher than the rest of the crater floor because it has not been covered by the dark lavas. Much of the area is coated with a diffuse red deposit that Galileo scientists believe has condensed from sulfur gas escaping from volcanic vents. The floor of Tupan is covered with a surreal pattern of dark black, green, red, and yellow materials. The black material is recent, still-warm lava. The yellow is presumed to be a mix of sulfurous compounds, and the green appears to form where red sulfur has interacted with the dark lavas. While Galileo scientists have found previous evidence for both molten sulfur and molten rock on Io, this image shows the best evidence to date of chemical reactions taking place between the two.<br /><br />The intermingled patches of sulfur and lava are difficult to explain. The yellowish sulfur may be melting from within the crater walls over solidified but warm lava. The sulfur may boil away from the areas too hot for liquid sulfur to sit on, leaving patches where the dark lava is still visible.<br /><br />North is to the top of the imag <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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3488

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Loki Patera.<br /><br />High temperatures observed by NASA's Galileo spacecraft along the western edge of the Loki volcano on Jupiter's moon Io may indicate freshly exposed material at the shore of a lava lake.<br /><br />Two temperature maps of the southern portion of Loki show hot (lower right) and hotter (upper right) features based on infrared-wavelength observations during an Oct. 16, 2001, flyby of Io. For context, they are shown beside a visible-wavelength picture (left) of the area taken during an earlier flyby.<br /><br />Loki is the most powerful volcano on Io. It has been active since at least 1979, when it was discovered by NASA's Voyager mission. Loki's dark volcanic crater, called a caldera, surrounds a light-colored island, as seen in the camera image (left). Previous observations by Galileo's instruments have shown that active lavas and still-cooling lava flows cover the floor of the caldera. In contrast, the island is cold and has no volcanic activity except in a narrow dark region that may be a crack or valley. Current volcanic activity appears in the two temperature maps from Galileo's near-infrared mapping spectrometer instrument. The lower right image shows where the surface is glowing at an infrared wavelength of 4.4 microns, with the yellow-orange coding correlated to temperatures of about 360 degrees Kelvin (188 Fahrenheit) and the reddish coding correlated to temperatures of about 430 Kelvin (314 Fahrenheit). The upper right image is at a wavelength of 2.5 microns, with the white streak correlated to temperatures of roughly 840 Kelvin (1,052 Fahrenheit). Each picture element averages the characteristics of an area about 2 kilometers (1.2 miles) across; smaller patches may be hundreds of degrees higher.<br /><br />Loki has puzzled scientists trying to determine what type of volcano it is. One idea holds it is an active lava lake with molten material under the crust. A competing view is it is a caldera whose floor is continuously flooded by lavas in s <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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3488

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Io has differentiated into layers. Understanding the number and composition of the layers is still being studied. Most scientist agree there is a core surrounded by mantle. A simple 2-layer (metallic core and a silicate mantle) model suggests the core is about 17-20 percent of Io's mass and has a radius of about half of Io's radius (Anderson et al. 1996). Another model (that assumes a pure iron core) suggests the core is 11-14 percent of Io's mass and has a radius of about one-third of Io's radius. Schubert (1997) used a three-layer model to suggest the presence of a thick (100-250 km) outer layer on Io. Several lines of evidence indicate that Io's metallic core is at least partly molten. Some models call for Io to have silica-rich crust about 40-60 km thick. The crust would be made of alkali-rich minerals, probably feldspars and nepheline. Much of the mantle may be pure forsterite (magnesian-rich olivine). <br /><br />The enormous gravitational forces of Jupiter cause heating within Io. Most of this heating is concentrated in the asthenosphere, estimated to be 50-100 km thick. Additional heating occurs deep in the mantle. Melting is probably located at the base of the lithosphere. Based on the amounts on energy released by Io's volcanoes each part of the interior has probably been remelted at least 100 times over the satellite's history. <br /><br />Andrew Brown.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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jmilsom

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Thanks for those interesting posts Andrew. <br /><br />I can see that it is easy to become an Iophile! Io is like a geologists pleasure planet! It will, indeed, be fascinating to see what changes there are since the last images were taken. To be able to observe the dynamic surface of Io on a day to day basis (i.e your orbiter) would really be exciting. I agree that the steady-state convection theory seems the most plausible for Loki Patera at this point in time, but you never know what the next images / data will turn up. NH will unfortunately give just a teasing and brief glimpse! <div class="Discussion_UserSignature"> </div>
 
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3488

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Yes you are right. New Horizons will only provide a sneak look, but hopefully enough detail will be visible to see what the current state of activity is.<br /><br />Also the Jupiter facing side will be 'fairly well' seen, but these images will be no where as good as those from Voyager 1, or a few select mug shots from Galileo (which concentrated on the Io farside, including the high resolution images).<br /><br />I have attached a nice Voyager 1 image of Loki (I know it is rather old, but is pretty good none the less). The 'raft' is very clearly visible on the dark sulphurous lava lake.<br /><br />I hope my orbiter / lander mission will be approved at some point.<br /><br />As you can tell, I am a real Iophile.<br /><br />I will post more later.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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jlougen

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I just came across this forum looking for updated articles on Loki Patera. I wanted to add a little bit of what I believe from a volcanologists standpoint of what we've observed at Loki Patera. I have been working on Loki Patera for almost 3 years as my Master's thesis research. What I've come to understand is that Loki Patera is a silicate volcano based on the NIMS and PPR data as well as modeled brightness temperatures in excess of 1000 K (Davies, GRL, 2003). Sulfur boils at temperatures around 400 K and the temperatures we've measured are way too high for a sulfur lava lake. <br />Also, the "raft" or "island" I don't think is a raft. Comparing the images that Voyager and Galileo took of Loki Patera, the "island" does not change shape, location or size in the roughly 20 years between missions and since we do have ground-based observations that show that Loki Patera has been active in between those missions, if the "island" were a raft we should see some change in at the very least location based on the convecting lava lake theory. Also, the PPR data and NIMS data should show warmer surface temperatures than they do for the "island" instead the "island" has the same surface temperature as the surrounding plains. Also, the cracks across the "island" make this a unique feature on Io (this is not seen anywhere else on Io). These cracks are shown to have a warm component to them based on the NIMS data. On Earth, this may indicate a resurgent dome. I think this is a theory that should be looked into further for Loki Patera.
 
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3488

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Hi jlougen,<br /><br />Welcome to SDC. Great post. <br /><br />I thought so too. The central island is mysterious as the one in Tupan Patera. I think they are analogous of Erta Ale in Ethiopia, a flat 'promontery' jutting out into the lava lake.<br /><br />I was one of those who petitioned to get JPL to image the Io 'nearside' during the I33 Encounter with the Galileo orbiter. Loki Patera would have been seen in very high resolution, had the imaging been approved, but NASA cited the very paltry sum of $1.25 million dollars to image Io & Amalthea (A34) could not be justified (yet have spent billions on the ISS) as well as potential 'safing'. Galileo did go into safing, but not until nine hours after the closest approach to Amalthea & after the Io encounter. <br /><br />Pathetic excuses really to not attempt to do it. <br /><br />However I have got my Io observations approved for the New Horizons Jupiter encounter next February, Loki Patera will be seen by the ALICE infrared camera, although very low resolution, should put a more accurate temperature measurement on the temperature of the lava lake in Loki Patera.<br /><br />I am trying to get a dedicated Io orbiter & / or lander mission. But due to my current poor health, been quite unwell recently, I just at the moment cannot cope. <br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
 
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silylene old

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jlougen, welcome to our forums!<br /><br />I hope you stay and participate. Thanks for your thought-provoking post. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>
 
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silylene old

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3488, I sure you you feel stronger and recover. I have always enjoyed your contributions here.<br /><br />I also wish JPL had been a little more bold with imaging in the Io and Amalthea encounter, as you mention. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>
 
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