Supervolcano on the Rise (broadcast Friday, November 9th, 2007)

The orange shapes in this image represent the magma chamber -- a chamber of molten and partly molten rock -- beneath the giant volcanic crater known as the Yellowstone caldera, which is represented by the rusty-colored outline at the top. Wu-Lung Chang, University of Utah.

The remnants of a supervolcano under Yellowstone National Park are on the rise -- though researchers say there's no cause for alarm. Work published this week in the journal Science reports that since 2004, the ground under Yellowstone has been rising at a rate of up to 7 centimeters per year.

It's no secret that the Yellowstone area is still quite active geologically -- that's what's responsible for the geysers and hot springs that make the park famous. The rate of rise, however, is surprising to the researchers studying the park.

"Our best evidence is that the crustal magma chamber is filling with molten rock," said Robert Smith, one of the authors of the report. "We have no idea how long this process goes on before there either is an eruption or the inflow of molten rock stops and the caldera deflates again." Smith and colleagues say the amount of material needed to cause the rise would involve a slug of molten rock roughly the size of the city of Los Angeles.

In this segment, Ira and guests talk about the new geology research being published this week, and Yellowstone's geologic history and future. Teachers, find more information about using Science Friday as a classroom resource in the Kids' Connection.