Fortunately, the surge doesn't seem to herald an imminent catastrophe, Smith said.

"At the beginning we were concerned it could be leading up to an eruption," said Smith, who co-authored a paper on the surge published in the December 3, 2010, edition of Geophysical Research Letters.
"But once we saw [the magma] was at a depth of ten kilometers, we weren't so concerned. If it had been at depths of two or three kilometers [one or two miles], we'd have been a lot more concerned."

But there are also many examples, including the Yellowstone supervolcano, where it appears the ground has risen and fallen for thousands of years without an eruption.

When the rate of increase slows, the theory goes, the magma likely moves off horizontally to solidify and cool, allowing the surface to settle back down.
Based on geologic evidence, Yellowstone has probably seen a continuous cycle of inflation and deflation over the past 15,000 years, and the cycle will likely continue, Smith said.

Scientists think a swelling magma reservoir four to six miles (seven to ten kilometers) below the surface is driving the uplift. Fortunately, the surge doesn't seem to herald an imminent catastrophe, Smith said.