They point out that, literally, the landscape of Yellowstone is always shifting. Last year, typical for the era when such measurements have been made, there were about 2,300 earthquakes in the park.

"Geologists usually look at something that formed millions of years ago and is now dead," said Lisa Morgan, a U.S. Geological Survey geologist. "But in Yellowstone, it's something that's happening right now."

The bulge, discovered with newly employed high-tech gadgetry and techniques led by Morgan last year, might be relatively new. Or, she said, it could have formed millennia ago.

"I don't know whether this thing is active now in terms of inflation or not," Morgan said.

So what set off the panic in the it's-time-to-drill crowd? A few combinations of coincidence and research.

First, state-of-the-art mapping revealed some features of Yellowstone that were previously unknown. Next were more obvious changes to the Norris geyser basin that were taking place. Combined with what scientists see as sensational press coverage, these triggered alarm in some circles.

Beginning in 2002, Morgan led a team that produced the first detailed topographical maps of the bottom of Lake Yellowstone — a pristine basin fed by 144 mountain streams and drained by the Yellowstone River.

Morgan deployed robotic submarines. She bounced sonar waves off the lake bed and at frequencies that penetrated deeper into that bottom. She ordered magnetic measurements of the rock. The result was a map whose precision befit the digital age.

"It's like having the cataracts taken off of your eyes," she said.

The scientific view was delightful. Through roughly the middle of the lake ran the edge of the Yellowstone caldera, that sunken supervolcano crater, a tad straighter and more to the east than previously thought.

In a northwestern corner of the lake was a spire field, column after column of towers ranging from just more than 3 feet to a little less than about 30 feet wide and sometimes more than two stories high.

Morgan said they were formed around hydrothermal vents, where sulfur-laced, super-heated water jets into the lake. The sulfur attracts bacteria. The bacteria become filled with silica and build layer upon layer — stalagmite-style — over the eons.

Perhaps most dramatic was the discovery of the bulge, what Morgan labeled an "inflated plain," to suggest it is evidence of pressure from below the lake nudging at the earth's skin.

Roughly the size of a few city blocks, she said it was pocked with hydrothermal vents that demonstrate it is close to the magma chamber below and possibly under more pressure that other places in the caldera.