BILLINGS, Mont. -

Scientists from the United States and Denmark are launching a study to map out the underground plumbing system responsible for Old Faithful and other blasting geysers and boiling hot springs of Yellowstone National Park.

Throughout November the research team will fly over the park with a helicopter that will hoist a giant, hoop-shaped electromagnetic device that acts like an X-ray.

They want to peer beneath the earth's surface to determine where and how water flows among geysers.

Lead scientist Carol Finn with the U.S. Geological Survey says the team also hopes to gain insights into the infrequent but sometimes massive hydrothermal explosions that occur in the park. A crater left by one of those explosions is several kilometers across.

Finn says similar work elsewhere in the U.S. has helped reveal hazards from volcanoes.