Huge landslides spotted on tiny moon (+video)
Scientist studying Saturn's icy moon of Iapetus have detected several 50-mile-long landslides, a phenomenon that they attribute to flash heating.
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Scientists think that the landslides are relatively recent, and could have been triggered by impacts in the last billion years or so.Skip to next paragraph
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"You don't see a lot of small craters on the landslide material itself," Singer said, although the surrounding terrain boasts evidence of bombardment. Over time, landscapes tend to be dotted by falling rocks, so the less cratered a surface is, the younger it is thought to be. [Photos of Saturn's Moons]
Resting on the ridges and walls, the material gradually becomes more unstable. Close impacts could set them off, but powerful, distant impacts reverberating through the ice could also send them tumbling.
The research was published in the July 29 issue of the journal Nature Geoscience.
Connecting ice and rock
Differences in gravity, atmosphere and water content make landslides seen on Iapetus difficult to duplicate in the laboratory. But the fact that they happen on different types of worlds makes it more likely that the mechanism triggering the extended slide is dependent on things unique to either environment.
"We have them on Iapetus, Earth and Mars," Singer said. "Theoretically, they should be very similar."
Singer pointed out the implications for friction within fault lines, which produces earthquakes. As plates on Earth move, the rocks within a fault snag on each other, until forces drag them apart. But sometimes, the faults slip farther than scientists can explain based on their understanding of friction. If flash heating occurs within the faults, it could explain why the two opposing faces slide the way they do, and provoke a better understanding of earthquakes.
In such cases, flash heating would cause minerals to melt and reform, producing an unexpected material around the faults. Some such materials have been identified at the base of long landslides on Earth.
"If something else is going on, like flash heating, or something making [the material] have a lower coefficient of friction, this would affect any models that use the coefficient of friction," Singer said.
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