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Io - Pele Volcano
Pele Volcano & Pillan Patera

Left: Volcano Pele, named after the legendary Hawaiian volcano goddess, has a heart formed from volcanic ejecta.

Table of Contents
Pele Volcano & Pillan Patera
Parent Planet
Io Science
Pele Eruption
Eruption of Pele. [ more ]
Pele is one of the largest visible volcanic features on Io and was also the first active volcano discovered on another world. Pele was name after the legendary Hawaiian volcano goddess. The large red ring that is in a heart shape in the Voyager images was formed from sulfur fallout originating from Pele's plume and reaches more than 1,300 kilometers (808 miles) in diameter. Pele's plumes have been observed to reach heights of 400 kilometers. The dramatic picture to the right was taken by Voyager 1. The plume rises to over 300 kilometers above the surface in an umbrella-like shape. The fallout covers an area the size of Alaska. Pele's vent is a dark spot just north of the triangular-shaped plateau (right center).

The vent region of Pele has an intense high-temperature hot spot that is remarkably steady, unlike lava flows that erupt in pulses, spread out over large areas, and then cool over time. This leads scientists to hypothesize that there must be an extremely active lava lake at Pele that constantly exposes fresh lava. Galileo's camera snapped a close-up picture showing part of the volcano glowing in the dark. Hot lava, at most a few minutes old, forms a thin, curving line more than six miles (10 kilometers) long and up to 150 feet (50 meters) wide. Scientists believe this line is glowing liquid lava exposed as the solidifying crust breaks up along the caldera's walls. This is similar to the behavior of active lava lakes in Hawaii, although Pele's lava lake is a hundred times larger.

Pele's Glow Pele's Glow
Brightly glowing lava from the volcano Pele is seen in this image taken by NASA's Galileo spacecraft as it receded from its close flyby of Jupiter's moon Io. The image at left shows Io's surface in approximately true color, centered on the large red ring of sulfur that was deposited by Pele's plume. A false color infrared composite of the same region is shown on the right. The dark red dot at the center of the ring is the glow of hot lava at the heart of the volcano. Temperatures up to 1,027 degrees celsius have been previously measured for Pele's lava. The glow is bright enough to be imaged in daylight, allowing scientists to precisely pinpoint the eruptive center.

Pele Glowing in the Dark Io's Pele Glowing in the Dark
In this high-resolution view from the Galileo spacecraft, the Pele hot spot shows a complex pattern of areas glowing in the dark, including areas likely to be fresh overturning of a lava lake's crust. This picture reveals details down to 60 meters (200 feet) in length. Red indicates the most intense combination of temperature and area; blue indicates cooler materials or smaller patches of hot materials. Scientists believe the Pele hot spot has a lava lake inside a volcanic crater or caldera, where cooled crust of the lava lake is breaking up against the wall and hotter lava appears from underneath.

Pillan Patera

Pillan Pateria
Changes in Pillan Pateria. [ more ]
These images of Io show the results of a dramatic event that occurred at Pillan Patera during a five-month period. The changes occurred between the time Galileo acquired the left frame, during its seventh orbit of Jupiter, and the right frame, during its tenth orbit. A new dark spot, 400 kilometers (249 miles) in diameter, which is roughly the size of Arizona, surrounds Pillan Patera. Pele, which produced the larger plume deposit southwest of Pillan, also appears different than it did during the seventh orbit, perhaps due to interaction between the two large plumes. Pillan's plume deposits appear dark at all wavelengths. This color differs from the very red color associated with Pele, but is similar to the deposits of Babbar Patera, the dark feature southwest of Pele.

The Galileo spacecraft indicate that the lava at Pillan Patera exceeded 1,700 degrees kelvin (2,600 degrees Fahrenheit) and may have reached 2,000 degrees kelvin (3,140 degrees Fahrenheit). The hottest eruptions on Earth today reach temperatures of about 1,500 kelvin (2,240 degrees Fahrenheit), but hotter lava erupted billions of years ago.

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