Yellowstone National Park – Yellowstone National Park, on the site of a giant volcano, has begun swelling up. Scientists say it could mean
that molten rock is accumulating beneath the surface.
But a professor of geophysics at the University of Utah --
Robert Smith -- says there is no evidence of an imminent volcanic
eruption. He says many giant volcanic craters around the world go
up and down over decades, without erupting.
Smith and colleagues report in Friday's issue of the journal
"Science" that the flow of the ancient Yellowstone crater has
been moving upward, almost 3 inches per year, for the past three
years. The scientists say that's more than three times faster than
has been observed, since measurements began in 1923.
The volcano at Yellowstone produced massive eruptions 2 million,
1.3 million and 642,000 years ago, all larger than the 1980
eruption of Mount St. Helens.