![]() It might explain, for example, why there are often recent eruptions near mountains. "It's a neat demonstration of how things might actually work," McKinnon said. When it breaches the surface, it actually overshoots, forming a scarp, or cliff, and stretching the surface of the overhanging block. The simulations show that the strain localizes to a single fracture, or fault, that starts deep in the lithosphere and rips through the rock all the way to the surface. We thought we could mimic this by beveling in the edges of a box, squeezing it as you might an accordion. "People have been squeezing planetary interiors forever to see what happens," McKinnon said, "but we're applying the squeeze differently, because on Io compression increases with depth the surface is not in compression. The numerical experiment described in Nature Geoscience tests this hypothesis through simulation. McKinnon and his former student, Paul Schenk, now at the Lunar and Planetary Institute in Houston, wrote a paper explaining this hypothesis in 2001. ![]() "All that lava spewed on the surfaces pushes downward and, as it descends, there's a space problem because Io is a sphere, so you end up with compressive forces that increase with depth." "The planetary community has thought for a while that Io's mountains might be a function of the fact that it is continuously erupting lava over the entire sphere," McKinnon said. Bland, a research space scientist at the USGS Astrogeology Science Center in Flagstaff, Ariz., publish a computer model that is able to make numerical mountains that look much like the jutting rock slabs on Io. In the May 16 online advance issue of Nature Geoscience, McKinnon and Michael T. Since Io buries the evidence of its tectonic processes under a continually refreshed coating of lava (adding 5 inches a decade), the scientists have turned increasingly to computer simulations to solve the problem. By what process consistent with everything that is known about Io could these bizarre mountains have formed? Louis, the mountains of Io are an intriguing puzzle. From space, they look rather like the blocky chips in the fancier kind of chocolate chip cookie.įor planetary geophysicists like William McKinnon, professor of earth and planetary science in Arts & Sciences at Washington University in St. While we favor majestic ranges stretching from horizon to horizon, the mountains on Io are isolated peaks of great height that jut up out of nowhere. They also don't look like mountains on our home world. ![]()
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