New underground imaging technology will eliminate the guesswork in unearthing the skeletal remains of what is thought to be the longest dinosaur ever discovered.

That's the opinion of David Gillette, a paleontologist in charge of excavating the remains of the creature, believed to be the first of its kind found. Gillette named it "seismosaurus" for its "earth-shaking" size. The dig site is in New Mexico.The seismosaurus, a plant eater that lived 144 million years ago, was at least 110 feet long and weighed 40 tons or more. Other supergiants weighed more than the seismosaurus, but it is believed to be the longest. The previous record-holder was the diploducus - at about 87 feet.

"In a general sense, the technology world has never been brought to the field of paleontology (the study of prehistoric life through the use of fossils)," said Gillette. "It holds great promise toward improving our effectiveness."

By determining the exact location of the seismosaurus bones in advance, Gillette said he and his team can avoid the hit-and-miss digging that is commonplace at excavation sites.

Alan Witten, an Oak Ridge, Tenn., scientist, is testing a "sonic-geophysical-imaging" system developed at Oak Ridge National Laboratory. The technique uses sound waves to get an accurate picture of underground features - such as buried dinosaur bones. The acoustical technique differentiates the bones from the surrounding sandstone by the length of time it takes sound waves to pass through each material.

Gillette said he also is using information from sensing techniques developed at Los Alamos National Laboratory and Sandia National Laboratories.

Gillette, who until recently was curator of the New Mexico Museum of Natural History, is state paleontologist for Utah. He has been working since 1985. The first bones were found in 1979 by a hiker.